Transparent electroconductive film, method for manufacture thereof, and touch panel

ABSTRACT

A transparent conductive film comprising a polymer film and a transparent conductive layer provided thereon, especially a transparent conductive film improved in durability and mechanical and electrical properties, a process for the preparation thereof, and a touch panel provided with the transparent conductive film, as well as transparent conductive plate and the process for the preparation thereof. The transparent conductive film comprising a polymer film, an undercoat layer and a transparent conductive layer which are superposed in this order, and the undercoat layer contains a compound having at least one selected from an amino group and a phosphoric acid group.

BACKGROUND OF INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a transparent conductive filmhaving a polymer film and a transparent conductive layer providedthereon, especially a transparent conductive film improved in durabilityand mechanical and electrical properties, a process for the preparationthereof, and a touch panel provided with the transparent conductivefilm, as well as transparent conductive plate and the process for thepreparation thereof.

[0003] 2. Description of the Related Art

[0004] A touch panel according to resistance sensitive system, in whichsignals are input by pushing a panel with a fingertip or pen andbringing the panel in contact with an opposite electrode to turn onelectricity, is advantageous to enable reduction of the size, weight orthickness. Therefore, the touch panel is widely used in input equipmentsof various home appliances and portable terminals.

[0005] The touch panel according to resistance sensitive system has astructure that an upper electrode comprising a polymer base film, anundercoat layer and a transparent conductive layer superposed in thisorder is laminated on a lower electrode comprising a plastic or glassthick plate and a transparent electrode formed thereon through spacers,such that the transparent conductive layer and transparent electrodeface each other. When a display surface of the upper electrode is pushedwith a fingertip or pen, the surface comes in contact with an oppositeelectrode to turn on electricity. Generally, a hard coat layer is formedon the display surface of the upper electrode to protect the polymerbase film.

[0006] The undercoat layer is generally provided to improve bondingstrength between the polymer (base) film and transparent conductivelayer and prevent peeling of the transparent conductive layer caused byrepetition of the pushing.

[0007] As the transparent conductive layer usable in the touch panel,for example, JA60-131711 describes a transparent conductive layersubjected to an annealing treatment to improve mechanical and chemicalproperties, the layer being provided on an undercoat layer of organicsilicon compound. JA02-66809 describes a composite of a substrate, anadhesive layer, a substrate and a transparent conductive layer, in whichthe adhesive layer serves to relax the stress applied to the transparentconductive layer.

SUMMARY OF THE INVENTION

[0008] It has revealed that the undercoat layer described in JA02-66809does not bring about satisfactory bonding strength between the polymerfilm and transparent conductive layer and therefore the transparentconductive layer is apt to be exfoliated when it undergoes a durabilitytest by writing. Hence, a touch panel provided with the transparentconductive layer is lowered in the electrical properties anddeteriorated in the appearance.

[0009] In view of the above-mentioned problems, the object of thepresent invention is to provide a transparent conductive film havingimproved bonding strength (adhesion) between a transparent conductivelayer and an undercoat layer, and showing excellent mechanicalproperties, electrical properties and durability, and a touch panelprovided with the transparent conductive film (first and secondinventions).

[0010] Further, the composite using the adhesive layer described inJA02-66809 uses polyurethane or rubber as an adhesive. According tostudy of the present inventors, however, the touch panel having thecomposite did not show a sufficient durability. In more detail, when asurface of an upper electrode prepared using the composite repeatedlyundergoes input operation by a pen or fingertip, the transparentelectrode generates crack and peeling from the polymer film in course oftime. The damage such as the crack or peeling reduces the electricalproperties such as uniformity of electrical resistance values(resistivities), and hence does not bring out the excellent durability.According to further study of the present inventors, it has beenrevealed that the damage is frequently caused by insufficient bondingstrength between an adhesive layer and a PET (polyethyleneterephthalate) film usually employed as a substrate for a composite ofsubstrate/adhesive layer/substrate.

[0011] The object of the present invention is to provide a touch panelin which the above problems are solved, and in which peeling between atransparent conductive layer and an undercoat layer does not occur andthe transparent conductive layer is not damaged even for long-term useto show excellent durability, and further which can be easily prepared,and further to provide a transparent conductive plate usable forpreparing the touch panel (a third invention).

[0012] The touch panel provided with the upper and lower electrodesusing the same kind of transparent conductive layer described inJA02-66809 does not show excellent durability because resistance toscratching of the transparent conductive layer on the polymer film asthe upper electrode is poor.

[0013] As for the electrode for the touch panel, JA02-194943 describesthat a transparent conductive layer of ITO (tin indium oxide) is formedand then the ITO is subjected to heat treatment to be crystallized inorder to improve the durability as above. However, the transparentconductive layer is a polymer film, which is restricted in enhancementof heat resistance. Further, it is necessary to conduct the heattreatment at 150° C. for a relative long time period to enhance the heatresistance, which results in disadvantage in terms of productivity andcost.

[0014] The present inventors have eagerly studied to improve thedurability of the upper and lower electrodes, and consequently foundthat, in the upper and lower electrodes using the same kind oftransparent conductive layer, the repetition of input operation with apen or fingertip generates fusing between the upper and lower electrodesand further produces crack and peeling of the transparent conductivelayer from the polymer film in course of time. The damage such as thecrack or peeling reduces the electrical properties such as uniformity ofelectrical resistance values, and hence does not bring out the excellentdurability.

[0015] The object of the present invention is to provide a transparentconductive film in which the above problems are solved, and which is notdamaged even for long-term use to show excellent durability, and furtherwhich can be easily prepared, and further to provide a process for thepreparation of this film (a forth invention).

[0016] Moreover, the touch panel according to resistance sensitivesystem needs a transparent conductive layer having high electricalresistance (500Ω/□). ITO has a low volume resistivity, and therefore itis necessary to reduce a thickness of the ITO for obtaining thetransparent conductive layer of high resistivity. However, it isdifficult to control the resistivity in case the thickness of film isreduced.

[0017] The object of the present invention is to provide a transparentconductive layer in which the above problems are solved, and which isnot damaged even for long-term use and prevents fusing to the lowerelectrode and further has good grinding resistance and excellentdurability, and furthermore of which thickness and electrical resistancecan be easily controlled, and further to provide a process for thepreparation of this film (a fifth invention).

[0018] Further, the object of the present invention is to provide atouch panel provided with any of the above transparent conductive films.

[0019] Furthermore, as mentioned above, according to study of thepresent inventors, it has been revealed that the composite prepared byusing the adhesive layer described in JA02-66809 shows insufficientdurability and therefore occurrence of crack and peeling of thetransparent electrode from the polymer film in course of time. Thedamage such as the crack or peeling reduces the electrical propertiessuch as uniformity of electrical resistance values, and hence does notbring out the excellent durability. According to further study of thepresent inventors, it has been revealed that the damage is frequentlycaused by insufficient bonding strength between an adhesive layer and aPET (polyethylene terephthalate) film usually employed as a substratefor a composite of substrate/adhesive layer/substrate.

[0020] The object of the present invention is to provide a touch panelin which the above problems are solved, and which does not suffer frompeeling between the polymer film and the adhesive layer even forlong-term use and further damage of the transparent conductive film, andwhich has excellent durability, and further to provide a transparentconductive film useful in the touch panel, and furthermore to providethe transparent conductive plate useful in the touch panel and a processfor the preparation of this plate (a sixth invention).

[0021] As described previously, the object of the present invention (thefirst to sixth inventions) is to provide a transparent conductive film,a transparent conductive plate, a process for the preparation of theseand a touch panel using these film or panel, which are improved indurability.

[0022] The above objects are attained by the following inventions:

[0023] The firs

[0024] t invention is provided by a transparent conductive filmcomprising a polymer film, an undercoat layer and a transparentconductive layer which are superposed in this order, wherein theundercoat layer contains a compound having at least one selected from anamino group and a phosphoric acid group.

[0025] By using the transparent conductive film provided the undercoatlayer containing the amino group and a phosphoric acid group, theresultant touch panel is improved in bonding strength between theundercoat layer and transparent conductive layer, free from occurrenceof peeling or falling of the transparent conductive layer from thepolymer film, and shows excellent durability.

[0026] In the first invention, the transparent conductive layerpreferably comprises at least one selected from indium oxide, tin oxide,zinc oxide, indium oxide-tin oxide (ITO; i.e., indium-doped tin oxide),antimony oxide-tin oxide (ATO; i.e., antimony-doped tin oxide), and zincoxide-aluminum oxide (ZAO; i.e., aluminum-doped zinc oxide). Especiallypreferred is indium oxide-tin oxide (ITO).

[0027] The compound having amino group is preferably derived from acompound selected from dialkylaminoalkyl methacrylate and asilane-coupling agent having an amino group, and the compound havingphosphoric acid group is preferably derived from a compound selectedfrom 2-methacryloyloxyethyl phosphate anddipehnyl-2-methacryloyloxyethyl phosphate.

[0028] A protective layer comprising a polymeric compound is preferablyprovided on the transparent conductive layer (the preferred embodimentsare described later).

[0029] The transparent conductive film has preferably a structurewherein a polymer film having a transparent conductive layer thereonthrough an undercoat layer and another polymer film having a hardcoatlayer thereon, the two polymer films being bonded to each other throughan adhesive layer comprising polyolefin resin such that a surface havingno transparent conductive layer of the polymer film and a surface havingno hardcoat layer of another polymer film face each other (the preferredembodiments are described later).

[0030] The transparent conductive layer generally comprises a firsttransparent conductive layer comprising a first metal oxide and a secondtransparent conductive layer comprising a second metal oxide, and thesecond transparent conductive layer is formed under the conditiondifferent from the condition for forming the second transparentconductive layer (the preferred embodiments are described later).

[0031] It is preferred that the hardcoat layer is provided on a surfacehaving no transparent conductive layer of the polymer film, and that thepolymer film comprises polyethylene terephthalate.

[0032] When signals are input onto the touch panel by pushing it with apen or fingertip, the upper electrode receives increased force comparedwith the lower electrode to deform whereby falling and peeling of thetransparent conductive layer are apt to occur. Therefore the transparentconductive layer of the invention free from falling and peeling ispreferably used in the upper electrode.

[0033] Hence, the first invention is provided by a touch panelcomprising an upper electrode having a hard coat layer, a first polymerfilm, a first undercoat layer and a first transparent conductive layersuperposed in this order, and a lower electrode having a plastic orglass plate, a second polymer film, a second undercoat layer and asecond transparent conductive layer superposed in this order, the upperelectrode and the lower electrode being bonded to each other throughspacers such that both of the transparent conductive layers face eachother, wherein the upper electrode and/or the lower electrode includesthe transparent conductive film as described above.

[0034] As mentioned above, the transparent conductive film having afirst polymer film, a first undercoat layer and a first transparentconductive layer can be employed as an upper electrode of the touchpanel.

[0035] Further, a composite of the transparent conductive film of theinvention and a plastic or glass plate can be employed as a lowerelectrode of the touch panel. Moreover, a touch panel having excellentdurability can be obtained by using the transparent conductive film ofthe invention in the upper and/or lower electrodes.

[0036] The lower electrode preferably has a transparent plate, anadhesive layer, a polymer film and a (second) transparent conductivelayer superposed in this order, the adhesive layer comprising polyolefinresin (the preferred embodiments are described later). Further, thefirst transparent conductive layer of the upper electrode is preferablyformed from material different from the second transparent conductivelayer of the lower electrode (the preferred embodiments are describedlater).

[0037] The second invention is provided by a transparent conductive filmhaving a polymer film and a transparent conductive layer providedthereon, wherein a protective layer comprising a polymeric compound isformed on the transparent conductive layer.

[0038] By forming protective layer comprising a polymeric compound onthe transparent conductive layer, the resultant touch panel is free fromoccurrence of peeling or falling of the transparent conductive layerfrom the polymer film, and hence shows excellent durability.

[0039] The polymeric compound is preferably one or more resin selectedfrom acrylic resin, polyester resin, epoxy resin, urethane resin, phenolresin, maleic acid resin, melamine resin, urea resin, polyimide resinand silicon-containing resin. The resin is preferably silicon-containingresin, and those containing an amino group. Further, of these resins,preferred are thermosetting resins. The polymeric compound preferably isalkoxy-silane containing an amino group. Hence, the protective layer isespecially preferred to be a cured layer formed by curing alkoxy-silanecontaining an amino group.

[0040] Further, the protective layer preferably is a cured layer formedby curing UV-curable resin, whereby the formation of the layer can becarried out for a short time period.

[0041] The protective layer comprising a polymeric compound is generallyan extremely thin layer that does not have influence on conductivity inthe direction perpendicular to the surface of the layer. The thicknesspreferably is 1 to 1,000 nm, especially 1 to 100 nm.

[0042] The transparent conductive layer preferably is an indium-dopedtin oxide (ITO). The hard coat layer is preferably formed on the polymerfilm to protect the film. The undercoat layer is preferably formedbetween the transparent conductive layer and the polymer film to enhancethe bonding strength between the transparent conductive layer and thepolymer film and prevent falling and peeling of the transparentconductive layer. The polymer film preferably is a polyethyleneterephthalate (PET) film.

[0043] When signals are input onto the touch panel by pushing it with apen or fingertip, the upper electrode receives increased force comparedwith the lower electrode to deform whereby falling and peeling of thetransparent conductive layer are apt to occur. Therefore the transparentconductive layer of the invention free from falling and peeling ispreferably used in the upper electrode.

[0044] Thus, the transparent conductive film of the invention comprisingthe polymer film, the transparent conductive layer and the protectivelayer comprising a polymeric compound can be employed as an upperelectrode of the touch panel. Further the combination of the transparentconductive film with a plastic or glass plate can be employed as a lowerelectrode. Moreover, a touch panel obtained by using the transparentconductive film of the invention in the upper and/or lower electrodesshows excellent durability.

[0045] The third invention is provided by a transparent conductive filmcomprising a first polymer film having a transparent conductive layerprovided thereon, and a second polymer film having a hard coat layerprovided thereon, the two polymer films being bonded to through anadhesive layer such that two surfaces having no layer of the two polymerfilms face each other.

[0046] The polyolefin resin of the adhesive layer preferably comprisescopolymer of ethylene and vinyl acetate and/or (meth)acrylate. Further,the polyolefin resin of the adhesive layer preferably comprises a filmformed by curing copolymer of ethylene and vinyl acetate and/or(meth)acrylate, the curing generally being crosslinking by thermalpolymerization or photopolymerization. Thereby the adhesive layerbecomes tough to be improved in durability. Modulus of elasticity of thetough adhesive layer generally is 1×10³ to 1×10⁷ Pa, preferably 1×10³ to1×10⁶ Pa, especially 1×10⁴ to 1×10⁵ Pa.

[0047] Both or one of the polymer films preferably comprise polyethyleneterephthalate, whereby the durability is improved.

[0048] The transparent conductive layer preferably comprises at leastone selected from indium oxide, tin oxide, zinc oxide, indium-doped tinoxide (ITO), antimony-doped tin oxide (ATO), and aluminum-doped zincoxide. Especially preferred is indium oxide-tin oxide (ITO). Thereby thelayer has excellent conductive properties.

[0049] The undercoat layer is preferably provided between the polymerfilm and the transparent conductive layer. Further, the protective layeris preferably provided on the transparent conductive layer, whereby thedurability is further improved.

[0050] The invention is also provided by a touch panel comprising anupper electrode which comprises a first polymer film having a firsttransparent conductive layer thereon and a second polymer film having ahard coat layer thereon, the first and second films being bonded to eachother through an adhesive layer such that both of the reverse sides faceeach other, and a lower electrode which comprises a plastic or glassplate (transparent plate), a polymer film and a transparent conductivelayer superposed in this order, the upper electrode and the lowerelectrode being bonded to each other through spacers such that both ofthe transparent conductive layers face each other, wherein the upperelectrode includes any of the above-mentioned conductive films.

[0051] When signals are input onto the touch panel by pushing it with apen or fingertip, the upper electrode receives increased force comparedwith the lower electrode to deform whereby falling and peeling of thetransparent conductive layer are apt to occur. Provision of an adhesivelayer enables relaxation the received force (load). However, the load isapt to reduce bonding force between the plastic plate and the polymerfilm. The adhesive layer of the invention combines the above relaxationwith good bonding force between the plastic plate and the polymer film.Therefore the transparent conductive film having the adhesive layerwhich is free from falling and peeling of the transparent conductivelayer and reduction of the bonding force and which has excellentdurability is preferably used in the upper electrode. Hence, the use ofthe transparent conductive layer in the upper electrode brings about atouch panel having excellent.

[0052] The forth invention is provided by the transparent conductivefilm which can prevent fusing between the upper and lower electrodes,has excellent mechanical properties and good grinding resistance, and isfree from falling and peeling of the metal oxide, which can be obtainedby forming a usual metal oxide layer on a polymer film, and then forminganother metal oxide layer different in oxygen content, nitrogen content,crystalline state and surface shape (surface roughness) from the usualmetal oxide layer on the usual metal oxide layer.

[0053] In more detail, the forth invention lies in a transparentconductive film comprising a polymer film and transparent conductivelayer comprising metal oxide formed thereon by a vapor depositionprocess, wherein the transparent conductive layer comprises a firsttransparent conductive layer comprising a first metal oxide and a secondtransparent conductive layer comprising a second metal oxide, and thesecond transparent conductive layer is formed under the conditiondifferent from the condition for forming the first transparentconductive layer.

[0054] In the film, the transparent conductive layer preferablycomprises indium-doped tin oxide (ITO), aluminum-doped zinc oxide (ZAO)or antimony-doped tin oxide (ATO).

[0055] The first and second transparent conductive layers are formed bya vapor deposition process selected from a sputtering process and areactive sputtering process, especially the reactive sputtering process.

[0056] A target material used in the vapor deposition process preferablyis a ceramic target formed by sintering mixed metal oxides or an alloytarget made of metal oxide.

[0057] The second transparent conductive layer comprising the secondmetal oxide is preferably different from the first transparentconductive layer comprising the first metal oxide in at least oneproperty selected from oxygen content, nitrogen content, crystallinestate and surface shape.

[0058] The condition for forming the second transparent conductive layercomprising the second metal oxide by a sputtering process is preferablydifferent in pressure and deposition rate in the sputtering from that ofthe first transparent conductive layer comprising the first metal oxide.

[0059] In the transparent conductive film comprising a polymer film andtransparent conductive layer comprising metal oxide formed thereon,wherein the transparent conductive layer comprises a first transparentconductive layer comprising a first metal oxide and a second transparentconductive layer comprising a second metal oxide (the forth invention),it is preferred that the second transparent conductive layer isdifferent in oxygen content different from the first transparentconductive layer.

[0060] Further, in the transparent conductive film comprising a polymerfilm and transparent conductive layer comprising metal oxide formedthereon, wherein the transparent conductive layer comprises a firsttransparent conductive layer comprising a first metal oxide and a secondtransparent conductive layer comprising a second metal oxide (the forthinvention), it is preferred that the second transparent conductive layeris different in nitrogen content different from the first transparentconductive layer.

[0061] The transparent conductive layer comprising metal oxidepreferably is an ITO layer.

[0062] The forth invention is also provided by a touch panel comprisingthe above transparent conductive layer and a lower electrode havingtransparent plate (plastic or glass plate) and a polymer film providedwith a transparent conductive layer superposed in this order, thetransparent conductive film and the lower electrode being bonded to eachother through spacers such that both of the transparent conductivelayers face each other.

[0063] The forth invention is further provided by a process for thepreparation of the above transparent conductive film comprising thesteps of:

[0064] forming the first transparent conductive layer comprising thefirst metal oxide onto the polymer film by a vapor deposition process,and

[0065] forming the second transparent conductive layer comprising thesecond metal oxide onto the first transparent conductive layer by avapor deposition process under the condition different from that forforming the first transparent conductive layer.

[0066] The preferred embodiments of the transparent conductive film canbe applied to the above process. Examples of the metal oxides include,in addition to the metal oxides mentioned above, indium oxide, antimonyoxide, cadmium oxide and GZO.

[0067] The fifth invention of the present invention is provided by atransparent conductive plate comprising a transparent plate, an adhesivelayer, a polymer film and a transparent conductive layer superposed inthis order, wherein the adhesive layer comprises polyolefin resin.

[0068] The polyolefin resin of the adhesive layer preferably comprisescopolymer of ethylene and vinyl acetate and/or (meth)acrylate. Further,the adhesive layer of the polyolefin resin preferably comprises a filmformed by curing copolymer of ethylene and vinyl acetate, the curinggenerally being crosslinking by thermal polymerization orphotopolymerization. Thereby the adhesive layer becomes tough to beimproved in durability. Modulus of elasticity of the tough adhesivelayer generally is 1×10³ to 1×10⁷ Pa, preferably 1×10³ to 1×10⁶ Pa,especially 1×10⁴ to 1×10⁵ Pa.

[0069] The polymer film may be any film as long as it is transparent.Preferred examples of the film include optical films such aspolyethylene terephthalate (PET), acrylic resin, polycarbonate, andtriacetyl cellulose films. Thereby, the transparent conductive plate isimproved in durability.

[0070] The transparent conductive layer preferably comprises at leastone selected from indium oxide, tin oxide, zinc oxide, indium-doped tinoxide (ITO), antimony-doped tin oxide (ATO), and aluminum-doped zincoxide (ZAO). Thus the transparent conductive layer has goodelectrically-conductive properties.

[0071] The undercoat layer (mentioned above) is preferably formedbetween the polymer film and transparent conductive layer. On thetransparent conductive layer, the protective layer (mentioned above) ispreferably provided. Thereby, the transparent conductive plate isimproved in durability. The transparent plate is generally a plastic orglass plate. Preferred examples of the plastic plate include acrylicresin (especially polymethyl methacrylate), polycarbonate, polystyrene,polyolefin and amorphous polyolefin. The plastic plate is excellent inimpact resistance compared with the glass plate.

[0072] The invention also lies in a touch panel comprising an upperelectrode having a polymer film and a transparent conductive layerprovided thereon, and a lower electrode having a transparent plate, anadhesive layer, a polymer film and a transparent conductive layersuperposed in this order, the upper electrode and the lower electrodebeing bonded to each other through spacers such that both of thetransparent conductive layers face each other, wherein the lowerelectrode includes the transparent conductive plate described above

[0073] When signals are input onto the upper electrode of touch panel bypushing it with a pen or fingertip, the upper electrode receivesincreased force (load) to deform while the lower electrode alsoindirectly receives the force. Therefore in the lower electrode, fallingand peeling of the transparent conductive layer are also apt to occur.Provision of an adhesive layer enables relaxation of the received force(load). However, the load is apt to reduce bonding force between theplastic plate and the polymer film. The adhesive layer of the inventioncombines the above relaxation with good bonding force between theadhesive layer and the transparent plate and between the adhesive layerand the polymer film. Therefore the adhesive layer is free from fallingand peeling of the transparent conductive layer, and peeling between thetransparent plate and the polymer film, and further has excellentdurability. Thus, it is preferred that the transparent conductive platehaving the adhesive layer is used in the upper electrode.

[0074] Hence, the use of the transparent conductive plate of theinvention as the lower electrode brings about a touch panel havingexcellent.

[0075] Moreover, the above transparent conductive (plastic) plate, whichcomprises a transparent plastic plate, an adhesive layer, a polymer filmand a transparent conductive layer, can be advantageously prepared by aprocess comprising the steps of:

[0076] applying a material for forming an adhesive layer onto a surfacehaving no transparent conductive layer of a polymer film provided withthe transparent conductive layer,

[0077] introducing the polymer film provided with the adhesive layerinto a mold for molding such that the transparent conductive layer facesa surface of the mold and

[0078] injection molding a resin for forming a transparent plastic platein the mold provided with the polymer film to incorporate the polymerfilm and the resin.

[0079] The process can be also applied to the transparent conductiveplastic plate using an adhesive other than polyolefin.

[0080] The sixth invention is provided by a touch panel having excellentmechanical properties and free from falling and peeling of thetransparent conductive layer, which has a future that a firsttransparent conductive layer of an upper electrode is formed frommaterial different from that of a second transparent conductive layer ofa lower electrode whereby physical and chemical affinity between theupper and lower electrodes is interrupted.

[0081] In the touch panel, the first and second transparent conductivelayers generally are a film of metal oxide, a film of combination of twoor more metal oxides or a composite film mainly consisting of metaloxide, or a film comprising gold, copper, nickel, aluminum or palladium.The first and second transparent conductive layers preferably are acomposite film of two or more of metal oxides. Further, the firsttransparent conductive layer is preferably formed from materialsdifferent in at least one material from the second transparentconductive layer.

[0082] The first and second transparent conductive layers preferablycomprise at least one selected from indium oxide system, zinc oxidesystem, tin oxide system, antimony oxide system and cadmium oxidesystem. Further, the first and second transparent conductive layerspreferably comprise sintered material of indium oxide-tin oxide (ITO),sintered material of indium oxide-zinc oxide (IZO), sintered material ofantimony oxide-tin oxide (ATO), and gallium-doped zinc oxide (GZO). Itis especially preferred that one of the transparent conductive layers isITO while the other is IZO.

[0083] The first and second transparent conductive layers are preferablyformed by a physical vapor deposition selected from a vacuum vapordeposition process, a sputtering process, an ion plating process and alaser ablation process. The first and second transparent conductivelayers are preferably formed by a chemical vapor deposition.

BRIEF DESCRIPTION OF THE DRAWINGS

[0084]FIG. 1 is a section view showing an example of the transparentconductive film of the first invention according to the presentinvention.

[0085]FIG. 2 is a section view showing an example of the touch panel inwhich the transparent conductive film of the first invention is used inthe upper and lower electrodes.

[0086]FIG. 3 is a section view showing an example of the transparentconductive film of the second invention according to the presentinvention.

[0087]FIG. 4 is a section view showing an example of the upper electrodeof touch panel having the transparent conductive film of the secondinvention.

[0088]FIG. 5 is a section view showing an example of the lower electrodeof touch panel having the transparent conductive film of the secondinvention.

[0089]FIG. 6 is a section view showing an example of the transparentconductive film of the third invention according to the presentinvention.

[0090]FIG. 7 is a section view showing an example of the touch panel inwhich the transparent conductive film the third invention is used in theupper electrode.

[0091]FIG. 8 is a section view showing an example of the transparentconductive film of the forth invention according to the presentinvention.

[0092]FIG. 9 is a section view showing an example of the touch panelusing the transparent conductive film of the forth invention.

[0093]FIG. 10 is a section view showing another example of the touchpanel having the transparent conductive film of the forth invention.

[0094]FIG. 11 is a section view showing an example of the transparentconductive plate of the fifth invention according to the presentinvention.

[0095]FIG. 12 is a section view showing an example of the touch panel inwhich the transparent conductive plate the fifth invention is used inthe lower electrode.

[0096]FIG. 13 is a section view showing an example of the touch panel ofthe sixth invention.

[0097]FIG. 14 is a section view showing another example of the touchpanel of the sixth invention.

DETAILED DESCRIPTION OF THE INVENTION

[0098] Embodiments of the invention are explained in detail by referringto drawings.

[0099]FIG. 1 is a section view showing an example of the transparentconductive film of the first invention according to the presentinvention.

[0100] In the transparent conductive film of the invention, an undercoatlayer 3 and a transparent conductive layer 4 are superposed in thisorder on one side of a polymer film 2. Provision of the undercoat layer3 of the invention brings about enhancement of bonding strength betweenthe transparent conductive layer 4 and the undercoat layer 3, wherebythe transparent conductive layer 4 is prevented from falling or peelingfrom the undercoat layer 3.

[0101]FIG. 2 is a section view showing an example of the touch panel inwhich the transparent conductive film the first invention is used in theupper and lower electrodes. In FIG. 2, the transparent conductive filmis used as an upper electrode. A hardcoat layer 1 a is provided on oneside of a polymer film 2 a, and an undercoat layer 3 a and a transparentconductive layer 4 a are superposed in this order on the other side ofthe polymer film 2 a. Though the hardcoat layer 1 a may be not provided,it is preferably provided to protect the polymer film 2 a. Further, aprotect layer can be provided on the transparent conductive layer 4 a.

[0102] In FIG. 2, the transparent conductive film is also used as alower electrode. An undercoat layer 3 b and a transparent conductivelayer 4 b are superposed in this order on one side of the polymer film 2b, and spacers 5 are formed on the transparent conductive layer 4 b. Atransparent plate such as a plastic plate (e.g., acrylic resin orpolycarbonate plate) or a glass plate is bonded to the other side of thepolymer film 2 b through an adhesive layer 6.

[0103] Examples of materials of the polymer film 2, 2 a, 2 b includepolyester such as polyethylene terephthalate (PET) and polybutyleneterephthalate, acrylic resin such as polymethyl methacrylate (PMMA),polycarbonate (PC), polystyrene, cellulose triacetate (TAC), polyvinylalcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene,ethylene-vinyl acetate copolymer, polyvinyl butyral, metal-crosslinkedpolyethylene, copolymer of methacrylic acid, polyurethane andcellophane. Preferred are PET, PC, PMMA and TAC, especially PET, interms of the toughness.

[0104] A thickness of the polymer film, though depending upon the use ofthe transparent conductive film, is generally in the range of 13 μm to0.5 mm in the case of using as the upper electrode of touch panel. Whenthe film has the thickness of less than 13 μm, the upper electrodehaving the film does not show sufficient durability. When the film hasthe thickness of more than 0.5 mm, the resultant touch panel hasincreased thickness per se to injure the flexibility.

[0105] In case the transparent conductive film is used as the lowerelectrode, the thickness of the polymer film used in the lower electrodecan be set to the range more than the above range, for example in therange of 0.5 to 2 mm. However, the polymer film may have the samethickness as in the upper electrode because the film can be bonded to aplastic plate as mentioned later.

[0106] Examples of materials of the transparent conductive layer 4, 4 a,4 b provided on the polymer film 2, 2 a, 2 b include indium oxide, tinoxide, zinc oxide, indium oxide-tin oxide (ITO), antimony oxide-tinoxide (ATO), zinc oxide-aluminum oxide (ZAO), and SnO₂. Especiallypreferred is ITO.

[0107] When a thickness of the transparent conductive layer 4, 4 a, 4 bis too small, the layer cannot have sufficient conductivity. When thethickness is too large, the transparent conductive layer cannot haveenhanced conductivity corresponding to the increase thickness andsuffers from increased cost for forming film and increased thickness ofthe transparent conductive film. Thus, the thickness of the transparentconductive layer 4, 4 a, 4 b preferably is in the range of 1 to 500 nm,especially 5 to 100 nm.

[0108] Though the transparent conductive layer 4, 4 a, 4 b can be formedaccording to a conventional process, it is preferred to form the layerby a sputtering process.

[0109] In the transparent conductive film, the hardcoat layer 1 a may beprovided on one side of a polymer film 2 a, the side having no undercoatlayer 3 a and transparent conductive layer 4 a. Examples of the hardcoatlayer 1 a include an acrylic resin layer, an epoxy resin layer, aurethane resin layer, and a silicone resin layer. The thicknessgenerally is 1 to 50 μm.

[0110] Examples of materials used in the undercoat layer 3, 3 a, 3 binclude thermosetting resin and photo-curable resin containing at leastone of an amino group and a phosphoric group.

[0111] Examples of the thermosetting resin include phenol resin,resorcinol resin, urea resin, melamine resin, epoxy resin, acrylicresin, urethane resin, furan resin and silicone resin, which contain anamino group and a phosphoric group. The amino group and phosphoric groupcan be introduced into a main component or a hardener of thethermosetting resin.

[0112] Examples of the photo-curable resins (or compounds) include(meth)acrylate monomers such as 2-hydroxyethyl(meth)acrylate,2-hydroxyropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate,2-ethylhexylpolyethoxy(meth)acrylate, benzyl(meth)acrylate, isobornyl(meth)acrylate, phenyloxyethyl(meth)acrylate, tricyclodecanemono(meth)acrylate, dicyclopentenyloxyethyl(meth)acrylate,tetrahydrofurfuryl (meth)acrylate, acryloylmorpholine,N-vinylcaprolactam, 2-hydroxy-3-phenyloxypropyl(meth)acrylate,o-phenylphenyloxyethyl (meth)acrylate, neopentylglycol di(meth)acrylate,neopentyl glycol dipropoxy di(meth)acrylate, neopentyl glycolhydroxypivalate di(meth)acrylate, tricyclodecanedimethyloldi(meth)acrylate, 1,6-hexanediol di(meth)acrylate, nonanedioldi(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritoltri(meth)acrylate, pentaerythritol tetra(meth)acrylate,tris[(meth)acryloxyethyl]isocyanurate and ditrimethylolpropanetetra(meth)acrylate; and

[0113] the following (meth)acrylate oligomer such as:

[0114] polyurethane (meth)acrylate such as compounds obtained byreaction among the following polyol compound and the following organicpolyisocyanate compound and the following hydroxyl-containing(meth)acrylate:

[0115] the polyol compound (e.g., polyol such as ethylene glycol,propylene glycol, neopentyl glycol, 1,6-hexanediol,3-methyl-1,5-pentanediol, 1,9-nonanediol,2-ethyl-2-butyl-1,3-propanediol, trimethylolpropane, diethylene glycol,dipropylene glycol, polypropylene glycol, 1,4-dimethylolcyclohexane,bisphenol-A polyethoxydiol and polytetramethylene glycol;polyesterpolyol obtained by reaction of the above-mentioned polyol withpolybasic acid or anhydride thereof such as succinic acid, maleic acid,itaconic acid, adipic acid, hydrogenated dimer acid, phthalic acid,isophthalic acid and terephthalic acid; polycaprolactone polyol obtainedby reaction of the above-mentioned polyol with ε-caprolactone; acompound obtained by reaction of the above-mentioned polyol and areaction product of the above-mentioned polybasic acid or anhydridethereof and ε-caprolactone; polycarbonate polyol; or polymer polyol),and

[0116] the organic polyisocyanate compound (e.g., tolylene diisocyanate,isophorone diisocyanate, xylylene diisocyanate,diphenylmethane-4,4′-diisocyanate, dicyclopentanyl diisocyanate,hexamethylene diisocyanate, 2,4,4′-trimethylhexamethylene diisocyanate,2,2′,4-trimethylhexamethylene diisocyanate), and

[0117] the hydroxyl-containing (meth)acrylate (e.g., 2-hydroxyethyl(meth)acrylate, 2-hydroxyropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 2-hydroxy-3-phenyloxypropyl(meth)acrylate,cyclohexane-1,4-dimethylolmono(meth)acrylate, pentaerythritoltri(meth)acrylate or glycerol di(meth)acrylate);

[0118] bisphenol-type epoxy(meth)acrylate obtained by reaction ofbisphenol-A epoxy resin or bisphenol-F epoxy resin and (meth)acrylicacid.

[0119] The photo-curable resin can be employed singly or in combinationof two or more kinds. Especially, combination of urethane acrylate andacrylate monomer is preferred. The photo-curable resin can be usedtogether with thermo polymerization initiator, i.e., these can beemployed as a thermosetting resin.

[0120] Photopolymerization initiators can be optionally selecteddepending upon the properties of the photo-curable resin used. Examplesof the photopolymerization initiators include acetophenone typeinitiators such as 2-hidroxy-2-methyl-1-phenylpropane-1-on,1-hydroxycyclohexylphenylketone and2-methyl-1-[4-(methylthio)phenyl]-2-morphorino-propane-1-on; benzointype initiators such as benzylmethylketal; benzophenone type initiatorssuch as benzophenone, 4-phenylbenzophenone and hydroxybenzophenone;thioxanthone type initiators such as isopropylthioxanthone and2,4-diethythioxanthone. Further, as special type, there can be mentionedmethylphenylglyoxylate. Especially preferred are2-hidroxy-2-methyl-1-phenylpropane-1-on,1-hydroxycyclohexylphenylketone,2-methyl-1-[4-(methylthio)phenyl]-2-morphorinopropane-1-on andbenzophenone. These photopolymerization initiators can be employedtogether with one or more kinds of a conventional photopolymerizationpromoter such as a benzoic acid type compound (e.g.,4-dimethylaminobezoic acid) or a tertiary amine compound by mixing withthe promoter in optional ratio. Only the initiator can be employedsingly or in combination of two or more kinds. Especially,1-hydroxycyclohexylphenylketone (Irgercure 184, available fromChiba-Specialty Chemicals) is preferred. The initiator is preferablycontained in the photo-curable resin in the range of 0.1 to 10% byweight, particularly 0.1 to 5% by weight.

[0121] The undercoat layer of the invention contains a compound havingan amino group (primary, secondary or tertiary amino group) and/or aphosphoric acid group. Preferred examples of the compounds having aminogroup include compounds derived from at least one selected fromdialkylaminoalkyl(meth)acrylates such as dimethylaminoethyl methacrylateand diethylaminoethyl methacrylate, and amino group-containing silanecoupling agents such asN-β(aminoethyl)-γ-aminopropylmethyldimethoxysilane,N-β(aminoethyl)-γ-aminopropylmethyltrimethoxysilane,N-β(aminoethyl)-γ-aminopropylmethyltriethoxysilane,γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane,N-phenyl-γ-aminopropyltrimethoxysilane. Preferred examples of thecompounds having phosphoric acid group include compounds derived from atleast one selected from 2-methacryloyloxyethyl phosphate anddiphenyl-2-methacryloyloxyethyl phosphate. Especially preferred arecompounds derived from at least one selected from of dimethylaminoethylmethacrylate (Acryl ester DM, available from Mitsubishi Rayon Co.,Ltd.), and γ-aminopropyltrimethoxysilane (KBE903, available fromShin-Etsu Chemical Co., Ltd.), and 2-methacryloyloxyethyl phosphate(P1M, available from Kyoei Chemical Co., Ltd.).

[0122] A thickness of the undercoat layer preferably is in the range of0.01 to 100 μm, especially 0.1 to 10 μm, in order to ensure theexcellent transparency of the layer and the enhanced bonding strengthbetween the layer and the transparent conductive layer.

[0123] The undercoat layer can be formed by applying a coating liquid ofan appropriate composition onto a polymer film with a coater such as barcoater, and curing the coated layer by ultraviolet irradiation orheating.

[0124] The polymer film 2, 2 a, 2 b can be subjected to an appropriatetreatment such as a plasma treatment, corona treatment orsolvent-washing treatment according to a conventional method, before theundercoat layer 3, 3 a, 3 b is formed on the polymer film 2, 2 a, 2 b,in order to enhance the bonding strength of the thin layer to be formed.

[0125] Further, a surface of the hardcoat layer 1 a can be processed byan antiglare processing, or an AR treatment. Furthermore, anantireflection layer mentioned later can be provided on the hardcoatlayer.

[0126] As described previously, the first invention can adopt theembodiments of the second to sixth inventions mentioned later.

[0127] Subsequently, the embodiments of the second invention areexplained in detail by referring FIG. 3 to FIG. 5.

[0128]FIG. 3 is a section view showing an example of the transparentconductive film of the second invention according to the presentinvention. In the transparent conductive film of the invention, atransparent conductive layer 4 and a protective layer 8 comprising apolymeric compound are superposed in this order on one side of a polymerfilm 2. Provision of the protective layer 8 of the invention comprisinga polymeric compound leads to interruption of the interaction betweenthe transparent conductive layer and an opposite another transparentconductive layer, the interaction being derived from the affinities ofthe layers to be faced to each other. Thus, the transparent conductivefilm free from its falling or peeling and hence showing excellentdurability can be obtained.

[0129]FIG. 4 is a section view showing an example of the upper electrodeof touch panel having the transparent conductive film of the secondinvention. In FIG. 4, a hardcoat layer 1 a is provided on one side of apolymer film 2 a, and an undercoat layer 3 a, a transparent conductivelayer 4 a and a protective layer 8 comprising a polymeric compound aresuperposed in this order on the other side of the polymer film 2 a.

[0130]FIG. 5 is a section view showing an example of the lower electrodeof touch panel having the transparent conductive film of the secondinvention. In FIG. 5, an undercoat layer 3 b, a transparent conductivelayer 4 b and a protective layer 8 comprising a polymeric compound aresuperposed in this order on one side of the polymer film 2 a, andfurther spacers 5 are provided on the protective layer 8. A transparentplate 7 made of plastic material (e.g., acrylic resin or polycarbonate)is bonded to the other side of the polymer film 2 b through an adhesivelayer 6.

[0131] The material and thickness of the polymer film 2, 2 a, 2 b followthe description in the first invention. The material and thickness ofthe transparent conductive layer 4, 4 a, 4 b also follow the descriptionin the first invention.

[0132] The protective layer 8 comprising a polymeric compound, whichconstitutes a feature of the second invention, generally comprises oneor more resin selected from acrylic resin, polyester resin, epoxy resin,urethane resin, phenol resin, maleic acid resin, melamine resin, urearesin, polyimide resin and silicon-containing resin. There can bementioned, for example, acrylic resin derived from alkyl(meth)acrylateor (meth)acrylic acid, polyester resin derived from polyhydric alcohol(e.g., ethylene glycol and glycerol) and polybasic acid (e.g., succinicacid and phthalic acid), epoxy resin derived from, for example,epichlorohydrin and polyhydric phenol, urethane resin derived from, forexample, 2,4-and 2,6-tolylene diisocyanate and polyoxypropylene glycol,phenol resin derived from, for example, phenol, cresol or xylenol andformaldehyde, maleic acid resin derived from, for example, rosin-maleicanhydride adduct and polyhydric alcohol (e.g., glycerol andpentaerythritol), polyimide resin derived from, for example,pyromellitic anhydride and m-phenylene diamine, and silicon-containingresin derived from amino group-containing alkoxysilane.

[0133] The protective layer is preferably formed from a compositioncomprising the silicon-containing compound. The silicon-containing resinis generally derived from amino group-containing alkoxysilane such asaminotrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltriimethoxysilane,N-β(aminoethyl)-γ-aminopropylmethyldimethoxysi lane,γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane. Amain component of the composition preferably is a silane compoundrepresented by H₃N_(x)Si(OR)_(4-x), in which R represents an organicgroup, preferably methyl or ethyl, and x represents 0, 1, 2 or 3. Thecomposition is crosslinked in three-dimensions bydehydration-condensation of silanol group of the compound to form alayer having high hardness. The crosslinking is generally carried out byheating at 80 to 220° C. for 10 min. to one hour.

[0134] The protective layer is preferably formed from UV-curable resin.Examples of the UV-curable resins (or compounds) include (meth)acrylatemonomers such as 2-hydroxyethyl(meth)acrylate, 2-hydroxyropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 2-ethylhexylpolyethoxy(meth)acrylate, benzyl(meth)acrylate, isobornyl(meth)acrylate,phenyloxyethyl (meth)acrylate, tricyclodecane mono(meth)acrylate,dicyclopentenyloxyethyl (meth)acrylate,tetrahydrofurfuryl(meth)acrylate, acryloylmorpholine,N-vinylcaprolactam, 2-hydroxy-3-phenyloxypropyl (meth)acrylate,o-phenylphenyloxyethyl(meth)acrylate, neopentylglycol di(meth)acrylate,neopentyl glycol dipropoxy di(meth)acrylate, neopentyl glycolhydroxypivalate di(meth)acrylate, tricyclodecanedimethyloldi(meth)acrylate, 1,6-hexanediol di(meth)acrylate, nonanedioldi(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritoltri(meth)acrylate, pentaerythritol tetra(meth)acrylate,tris[(meth)acryloxyethyl]isocyanurate and ditrimethylolpropanetetra(meth)acrylate; and

[0135] the following (meth)acrylate oligomer such as:

[0136] polyurethane (meth)acrylate such as compounds obtained byreaction among the following polyol compound and the following organicpolyisocyanate compound and the following hydroxyl-containing(meth)acrylate:

[0137] the polyol compound (e.g., polyol such as ethylene glycol,propylene glycol, neopentyl glycol, 1,6-hexanediol,3-methyl-1,5-pentanediol, 1,9-nonanediol,2-ethyl-2-butyl-1,3-propanediol, trimethylolpropane, diethylene glycol,dipropylene glycol, polypropylene glycol, 1,4-dimethylolcyclohexane,bisphenol-A polyethoxydiol and polytetramethylene glycol;polyesterpolyol obtained by reaction of the above-mentioned polyol withpolybasic acid or anhydride thereof such as succinic acid, maleic acid,itaconic acid, adipic acid, hydrogenated dimer acid, phthalic acid,isophthalic acid and terephthalic acid; polycaprolactone polyol obtainedby reaction of the above-mentioned polyol with ε-caprolactone; acompound obtained by reaction of the above-mentioned polyol and areaction product of the above-mentioned polybasic acid or anhydridethereof and ε-caprolactone; polycarbonate polyol; or polymer polyol),and

[0138] the organic polyisocyanate compound (e.g., tolylene diisocyanate,isophorone diisocyanate, xylylene diisocyanate,diphenylmethane-4,4′-diisocyanate, dicyclopentanyl diisocyanate,hexamethylene diisocyanate, 2,4,4′-trimethylhexamethylene diisocyanate,2,2′,4-trimethylhexamethylene diisocyanate), and the hydroxyl-containing(meth)acrylate (e.g., 2-hydroxyethyl (meth)acrylate,2-hydroxyropyl(meth)acrylate, 4-hydroxybutyl (meth)acrylate,2-hydroxy-3-phenyloxypropyl(meth)acrylate,cyclohexane-1,4-dimethylolmono(meth)acrylate, pentaerythritoltri(meth)acrylate or glycerol di(meth)acrylate);

[0139] bisphenol-type epoxy(meth)acrylate obtained by reaction ofbisphenol-A epoxy resin or bisphenol-F epoxy resin and (meth)acrylicacid.

[0140] The UV-curable resin can be employed singly or in combination oftwo or more kinds. Combination of urethane acrylate and acrylatemonomer, especially combination of urethane acrylate withneopentylglycol diacrylate is preferred. The UV-curable resin can beused together with thermo polymerization initiator, i.e., these can beemployed as a thermosetting resin.

[0141] In case the protective layer comprising polymeric compound isformed using the UV-curable resin, photopolymerization initiators areused to cure the resin. Examples of the photopolymerization initiatorsinclude acetophenone type initiators such as2-hidroxy-2-methyl-1-phenylpropane-1-on, 1-hydroxycyclohexylphenylketoneand 2-methyl-1-[4-(methylthio)phenyl]-2-morphorino-propane-1-on; benzointype initiators such as benzylmethylketal; benzophenone type initiatorssuch as benzophenone, 4-phenylbenzophenone and hydroxybenzophenone;thioxanthone type initiators such as isopropylthioxanthone and2,4-diethythioxanthone. Further, as special type, there can be mentionedmethylphenylglyoxylate. Especially preferred are2-hidroxy-2-methyl-1-phenylpropane-1-on,1-hydroxycyclohexylphenylketone,2-methyl-1-[4-(methylthio)phenyl]-2-morphorinopropane-1-on andbenzophenone. These photopolymerization initiators can be employedtogether with one or more kinds of a conventional photopolymerizationpromoter such as a benzoic acid type compound (e.g.,4-dimethylaminobezoic acid) or a tertiary amine compound by mixing withthe promoter in optional ratio. Only the initiator can be employedsingly or in combination of two or more kinds. Especially,1-hydroxycyclohexylphenylketone (Irgercure 184, available fromChiba-Specialty Chemicals) is preferred. The initiator is preferablycontained in the photo-curable resin in the range of 0.1 to 10 weight %,particularly 0.1 to 5 weight %.

[0142] Thickness of the protect layer 8, 8 a, 8 b is appropriately setdepending upon the used materials, and the light transmission anddurability required for the transparent conductive film. When thethickness is excessively reduced, the protective layer does notsufficiently serve to protect the transparent conductive layer. Incontrast, when the thickness is excessively increased, the protectivelayer is apt to reduce the transparency of the transparent conductivefilm or the electrically conductive properties of the transparentconductive layer, and also the transparent conductive film is so thickper se. Thus the thickness of the protective layer preferably is in therange of 1 to 1,000 nm, especially 1 to 100 nm.

[0143] The protective layer comprising polymeric compound of theinvention can be provided on the transparent conductive layer of theupper or lower electrode. Provision of the protective layer on only oneside of upper and lower electrodes brings about interruption of theaffinity interaction between the transparent conductive layers havingthe same or similar properties each other, whereby the transparentconductive film can be enhanced in durability.

[0144] The protective layer can be formed by applying a coating liquidof an appropriate composition onto a polymer film with a coater such asa doctor knife coater, bar coater, gravure roll coater, curtain coateror knife coater, and curing the coated layer by ultraviolet irradiationor heating.

[0145] In the transparent conductive film, a hardcoat layer 1 can beformed on one side of the polymer film 2 a where the transparentconductive layer 4 a is not formed in order to protect the polymer filmfrom damage caused by the pushing of a pen or fingertip. Further, anantireflection layer mentioned later can be provided on the hardcoatlayer.

[0146] Though the transparent conductive layer may be directly formed onthe polymer film, the undercoat layer 3 a, 3 b is generally providedbetween the polymer film 2 a, 2 b and the transparent conductive layer 4a, 4 b to enhance bonding strength between polymer film 2 a, 2 b and thetransparent conductive layer 4 a, 4 b preventing falling or peeling ofthe transparent conductive layer.

[0147] Materials for forming the undercoat layer 3 a, 3 b includeacrylic resin, urethane resin, epoxy resin, and products obtained byhydrolysis of organic silicon compound.

[0148] The undercoat layer can be formed by applying a coating liquid ofan appropriate composition onto a polymer film with a coater such as barcoater.

[0149] The treatment of the polymer film and the processing of thehardcoat layer can be carried out in the same manner as in the firstinvention.

[0150] As the spacers, those described in the first invention can beused.

[0151] The transparent conductive can be used in the same industrialfield as in the first invention.

[0152] Subsequently, the embodiments of the third invention areexplained in detail by referring FIG. 6 and FIG. 7.

[0153]FIG. 6 is a section view showing an example of the transparentconductive film of the third invention according to the presentinvention. In FIG. 6, a hardcoat layer 1 is provided on one side of apolymer film (second polymer film) 2 d, and a transparent conductivelayer 4 is provided on a polymer film (first polymer film) 2 c throughan undercoat layer 3 a, and the two polymer films are bonded to eachother through an adhesive layer 9 such that the reverse sides (sideshaving no layer) of the films face each other. The adhesive layer 9 ofthe invention comprises polyolefin resin and has high elastic modulusand high bonding strength to the polymer films on the both sides of theadhesive layer 9. Therefore, when signals are repeatedly input onto thetouch panel having the transparent conductive layer of the invention asthe upper electrode, the provision of an adhesive layer relaxes loadreceived by the input and the high bonding strength effectively of theadhesive layer prevents the peeling of the polymer film, wherebyexcellent durability can be obtained. In more detail, the provision ofan adhesive layer effectively prevents the crack, falling and peeling ofthe polymer film caused when signals are repeatedly input onto the touchpanel by pushing it with a pen or fingertip. Especially the adhesivelayer comprising crosslinked polyolefin can extremely enhance thebonding strength. The protective layer can be provided on thetransparent conductive layer.

[0154]FIG. 7 is a section view showing an example of the touch panel inwhich the transparent conductive film of the third invention is used inthe upper electrode. In the touch panel of FIG. 7, the transparentconductive film shown in FIG. 6 is used as an upper electrode, and acomposite having the transparent conductive layer 4 b and microdotspacers 5 superposed in this order on a transparent plate 7 is used as alower electrode. The touch panel is assembled by bonding the upper andlower electrodes such that both of the transparent conductive layersface each other. As is apparent from FIG. 7, the adhesive layer 9comprising polyolefin of the invention relaxes the load given fromoutside to extremely reduce the load applied to the transparentconductive layer.

[0155] The materials of the first and second polymer films 2 c, 2 dfollow the description in the first invention.

[0156] A thickness of the first and second polymer films, thoughdepending upon the use of the transparent conductive film, is generallyin the range of 13 μm to 0.5 mm in the case of using as the upperelectrode of touch panel. When the film has the thickness of less than13 μm, the upper electrode having the film does not have sufficientdurability. When the film has the thickness of more than 0.5 mm, theresultant touch panel has increased thickness to injure the flexibility.The thickness of the second polymer film is preferably set to be thinnerthan that of the first polymer film, especially in the range of 13 μm to0.2 mm.

[0157] The material and thickness of the transparent conductive layer 4,4 b follow the description in the first invention.

[0158] The transparent conductive layer can be formed according to aconventional process, preferably by a sputtering process.

[0159] In the third invention, the reverse side of the first polymerfilm having transparent conductive layer is bonded to the reverse sideof the second polymer film through the adhesive layer of the invention.

[0160] Examples of materials for forming the adhesive layer includepolyolefin resin such as polyethylene, polypropylene, and copolymer ofethylene and other monomer (e.g., vinyl acetate, acrylate, methacrylate,maleic anhydride, maleic acid). Preferred examples of the polyolefinresin include (I) ethylene/vinyl acetate copolymer having the vinylacetate content of 20 to 80 weight %, (II) ethylene/vinyl acetatecopolymer having the vinyl acetate content of 20 to 80 weight % andacrylate and/or methacrylate monomer content of 0.01 to 10 weight %, and(III) ethylene/vinyl acetate copolymer having the content of vinylacetate of 20 to 80 weight % and the content of maleic anhydride and/ormaleic acid of 0.01 to 10 weight %. These copolymers (I) to (III)preferably has Melt flow Rate (MRF) of 1 to 3,000, further 1 to 1,000,especially 1 to 800.

[0161] In these copolymers (I) to (III), the vinyl acetate content ispreferably 20 to 80 weight % as above, especially 20 to 60 weight %.When the content is less than 20 weight %, the crosslinked densityobtained by crosslinking (curing) the copolymer under heating isinsufficient. When the content is more than 80 weight %, the copolymers(I) and (II) show reduced softening temperature whereby the storagecomes to difficult to give practical problem while the copolymer (III)shows extremely reduced bonding strength and poor durability.

[0162] Further, in the copolymer (II) comprising ethylene, vinyl acetateand acrylate and/or methacrylate monomer, the acrylate and/ormethacrylate monomer content is preferably 0.01 to 10 weight % as above,especially 0.05 to 5 weight %. When the acrylate and/or methacrylatemonomer content is less than 0.01 weight %, the copolymer (II) does notshow sufficiently increased bonding strength, whereas the content morethan 10 weight % is apt to reduce the processing properties.

[0163] The acrylate and/or methacrylate monomer is generally esters ofacrylic or methacrylic acid and aliphatic alcohol of 1 to 20 carbonatoms, especially 1 to 18 carbon atoms, in which the alcohol may have asubstituent (e.g., epoxy group), for example, methyl acrylate, methylmethacrylate, ethyl acrylate, ethyl methacrylate and glycidylmethacrylate.

[0164] Further, in the copolymer (III) comprising ethylene, vinylacetate and maleic anhydride and/or maleic acid, the content of maleicanhydride and/or maleic acid is preferably 0.01 to 10 weight % as above,especially 0.05 to 5 weight %. When the content of maleic anhydrideand/or maleic acid is less than 0.01 weight %, the copolymer (III) doesnot show sufficiently increased bonding strength, whereas the contentmore than 10 weight % is apt to reduce the processing properties.

[0165] The polymer constituting the adhesive layer generally containsthe ethylene/vinyl acetate copolymer (I) to (III) in an amount of notless than 40 weight %, preferably not less than 60 weight %, especially100 weight % based on the total amount of the layer. In case of usingpolymer other than the above copolymer (I) to (III), for example, olefinpolymer having 20 or more weight % of ethylene and/or propylene in themain chain, poly vinyl chloride, and acetal resin.

[0166] As a crosslinking agent for thermo polymerizing and crosslinkingpolyolefin such as ethylene/vinyl acetate copolymer, an organic peroxideis generally employed.

[0167] As the organic peroxide, any materials that can be decomposed ata temperature of not less than 70° C. to generate radical(s) can beemployed. The organic peroxide is selected in the consideration offilm-forming temperature, condition for preparing the polymercomposition, curing (bonding) temperature, heat resistance of body to bebonded, storage stability. Especially, preferred are those having adecomposition temperature of not less than 50° C. in a half-life of 10hours.

[0168] Examples of the organic peroxide include2,5-dimethylhexane-2,5-dihydroperoxide,2,5-dimethyl-2,5-(t-butylperoxy)hexyne-3-di-t-butylperoxide,t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumylperoxide, α,α′-bis(t-butylperoxyisopropyl)benzene,n-butyl-4,4-bis(t-butylperoxy)valerate, 2,2-bis(t-butylperoxy)butane,1,1-bis(t-butylperoxy)cyclohexane,1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane,t-butylperoxybenzoate, benzoyl peroxide, t-butylperoxyacetate, methylethyl ketone peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, butylhydroperoxide, p-menthane hydroperoxide, p-chlorobenzoyl peroxide,hydroxyheptyl peroxide, chlorohexanone peroxide, octanoyl peroxide,decanoyl peroxide, lauroyl peroxide, cumyl peroxyoctoate, succinic acidperoxide, acetyl peroxide, t-butylperoxy(2-ethylhexanoate), m-toluoylperoxide, t-butylperoxyisobutylate and 2,4-dichlorobenzoyl peroxide. Theorganic peroxide can be used singly, or in combination of two or morekinds. The content of the organic peroxide is preferably in an amount of0.1 to 10 weight % based on the polyolefin resin such as ethylene/vinylacetate copolymer.

[0169] In case the polyolefin resin is cured by light, photosensitizer(photopolymerization initiator) is used instead of the organic peroxide,and it is generally used in an amount of 0.1 to 10.0 weight % based onthe polyolefin resin.

[0170] Examples of the photopolymerization initiator include hydrogendrawing type initiators such as benzophenone, methyl o-benzoyl benzoate,4-benzoyl-4′-methyldiphenylsulphide, isopropylthioxanthone,diethylthioxanthone, and methyl 4-(diethylamino)benzoate; intermolecularcleavage type initiators such as benzoin ether, benzoin isopropyl ether,benzoin dimethyl ketal; α-hydroxyalkylphenone type initiators such as2-hydroxy-2-methyl-1-phenylpropane-1-on, 1-hydroxycyclohexyl phenylketone, alkylphenyl glyoxylate, diethoxyacetophenone; α-aminoalkylphenontype initiators such as2-methyl-1-[4-(methylthio)phenyl]-2-morphorino-propanon-1 and2-bemzyl-2-dimethylamino-1-(4-morphorinophenyl)butanone-1; andacylphosphinoxide. The photopolymerization initiators can be usedsingly, or in combination of two or more kinds.

[0171] The adhesive layer of the invention preferably contains a silanecoupling agent. Examples of the silane coupling agent includevinylethoxysilane, vinyltris(β-methoxyethoxy)silane,γ-(methacryloxypropyl)trimethoxysilane, vinyltriacetoxysilane,γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane,β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltrichlorosilane,γ-mercaptopropylmethoxysilane, γ-aminopropyltriethoxysilane,N-β(aminoethyl)-γ-aminopropyltrimethoxysilane. Preferred isγ-(methacryloxypropyl)trimethoxysilane. The silane coupling agent can beused singly, or in combination of two or more kinds. The content of thesilane coupling agent is preferably in an amount of 0.01 to 10 weight %based on the polyolefin resin.

[0172] Further, the adhesive layer can contain an epoxy group-containingcompound as an adhesion-promoting agent. Examples of the epoxygroup-containing compound include triglycidyltris(2-hydroxyethyl)isocyanurate, neopentylglycol diglycidyl ether,1,6-hexanediol diglycidyl ether, allyl glycidyl ether, 2-ethylhexylglycidyl ether, phenyl glycidyl ether, phenol(ethyleneoxy)₅glycidylether, p-tert-butylphenyl glycidyl ether, diglycidyl adipate, diglycidylphthalate, glycidyl methacrylate and butyl glycidyl ether. The agent canbe used singly, or in combination of two or more kinds. The content ofthe agent is preferably in an amount of 0.1 to 20 weight % based on thepolyolefin resin.

[0173] The adhesive layer preferably contains acryloxy group-containingcompounds, methacryloxy group-containing compounds and/or epoxygroup-containing compounds for improvement or adjustment of variousproperties of layer (e.g., mechanical strength, adhesive property(bonding strength), optical characteristics such as transparency, heatresistance, light resistance, crosslinking rate), particularly forimprovement mechanical strength.

[0174] Examples of the acryloxy and methacryloxy group containingcompounds include generally derivatives of acrylic acid or methacrylicacid, such as esters and amides of acrylic acid or methacrylic acid.Examples of the ester residue include linear alkyl groups (e.g., methyl,ethyl, dodecyl, stearyl and lauryl), a cyclohexyl group, atetrahydrofurfuryl group, an aminoethyl group, a 2-hydroxyethyl group, a3-hydroxypropyl group, 3-chloro-2-hydroxypropyl group. Further, theesters include esters of acrylic acid or methacrylic acid withpolyhydric alcohol such as ethylene glycol, triethylene glycol,polypropylene glycol, polyethylene glycol, trimethylol propane orpentaerythritol.

[0175] Example of the amide includes diacetone acrylamide.

[0176] Examples of polyfunctional compounds (crosslinking auxiliaries)include esters of plural acrylic acids or methacrylic acids withpolyhydric alcohol such as glycerol, trimethylol propane orpentaerythritol; and further triallyl cyanurate, triallyl isocyanurate,diallyl phthalate, diallyl isophthalate and diallyl maleate.

[0177] The above compound containing acryloxy and the like can be usedsingly, or in combination of two or more kinds. The content of thecompound is preferably in an amount of 0.1 to 50 weight %, especially0.5 to 30 weight % based on the polyolefin resin. When the compound isused in an amount of more than 50 weight %, there are some cases wherethe preparation of a coating liquid for forming the adhesive layer comesto difficult or the coating properties of the liquid becomes poor. Theaddition of the compound of less than 0.1 weight % does not bring abouteffect by the addition.

[0178] Further the adhesive layer can contain a hydrocarbon resin forimproving processing properties such as laminating properties. Thehydrocarbon resin may be either natural resin or synthetic resin.Examples of the natural resins preferably include rosins, rosinderivatives and terpene resins. Examples of the rosins include gumresins, tall oil resins, wood resins. Examples of the rosin derivativesinclude hydrogenated rosins, disproportionated rosins, polymerizedrosins, esterificated rosins, and metal salts of rosins. Examples of theterpene resins include α-pinene resins, β-pinene resins, and terpenephenol resins. Moreover, as the natural resin, dammar, copal, shellaccan be used. Examples of the synthetic resins preferably includepetroleum resins, phenol resins, and xylene resins. Examples of thepetroleum resins include aliphatic petroleum resins, aromatic petroleumresins, cycoaliphatic petroleum resins, copolymer type petroleum resins,hydrogenated petroleum resins, pure monomer type petroleum resins, andcoumarone-indene resins. Examples of the phenol resins includealkylphenol resins and modified phenol resins. Examples of the xyleneresins include xylene resins and modified xylene resins. The content ofthe hydrocarbon resin, which can be appropriately selected, ispreferably in an amount of 1 to 200 weight %, especially 5 to 150 weight% based on the polyolefin resin.

[0179] The adhesive layer of the invention is generally prepared, forexample, by homogeneously mixing the composition composed of theabove-mentioned materials in an appropriate proportion, kneading themixture using an extruder or roll, and subjecting the kneaded mixture toa film-forming process using a calendar, roll, T-die extrusion orinflation to form a film having a predetermined dimension. A morepreferred process for forming the adhesive layer comprises the steps of:mixing and dissolving homogeneously the components in a good solvent,applying the resultant solution onto a separator coated closely withsilicone or fluoric resin (or onto a support) by means of flow-coaterprocess, roll-coater process, gravure-roll process, mayer-bar process orlip-die coating process, and vaporizing the solvent. Then, the resultantlayer is peeled from the support to obtain the adhesive layer(uncrosslinked).

[0180] The transparent conductive film can be obtained by bonding thesecond polymer film having the hardcoat layer formed thereon to thefirst polymer film having the transparent conductive layer formedthereon using the above crosslinkable adhesive layer. The bonding(laminating) may be carried out using calendar process, roll process,T-die extrusion process or inflation process at the same time with theformation of the adhesive layer. Otherwise, these layers and films canbe also bonded to each other by depressing them under heating using aroll or the like. After the bonding, the resultant laminated film ispreferably subjected to a degassing treatment by pressurizing andheating and/or a degassing treatment by vacuum heating to remove gas inthe adhesive layer. The degassing treatment by pressurizing is carriedout by placing the laminated film in a pressurizing and heating chambersuch as an autoclave to remove the gas (degas). In case a crosslinkableadhesive is used as an adhesive, it is crosslinked after the degassing.

[0181] When the crosslinking is performed by heating, the temperaturefor the heating, depending on kinds of crosslinkers (organic peroxides)generally is in the range of 70 to 150° C., preferably 70 to 130° C.,for 10 sec. to 120 min., preferably 20 sec. to 60 min. When thecrosslinking is performed by light, light source can adopt a largenumber of sources emitting light in wavelength of ultraviolet to visibleray, for example, super high-pressure, high-pressure and low-pressuremercury lamps, a chemical lamp, a xenon lamp, a halogen lamp, a mercuryhalogen lamp, a carbon arc lamp, and an incandescent electric lamp, andlaser beam. The irradiation (exposing) time is generally a few secondsto a few minutes, depending upon kinds of the lamp and strength oflight. To promote the curing, the laminate may be heated beforehand for40 to 120° C., and then the heated laminate may be exposed toultraviolet ray.

[0182] The pressure used when the polymer films are bonded to by theadhesive layer can be also set appropriately. The pressure is generally0 to 50 kg/cm², preferably 0 to 30 kg/cm². The thickness of the adhesivelayer formed as above is generally in the range of 5 to 100 μm.

[0183] The protective layer can be provided on the transparentconductive layer of the invention. The protective layer preferably is athin layer comprising, for example, SiC_(x), SiC_(x)O_(y), SiC_(x)N_(y),SiC_(x)O_(y)N_(y), in which x, y, z are an integer.

[0184] The thickness of the protective layer is appropriately setdepending upon materials used for forming the layer and lighttransmission and durability required to the transparent conductive film.When the thickness of the protective layer is excessively reduced, theprotective effect by the formation of the layer cannot be sufficientlyobtained. The excessively increased thickness brings about the reductionof transparency or conductivity, and further the increased thickness ofthe transparent conductive film. Thus the thickness of the protectivelayer is preferably in the range of 1 to 1,000 nm, especially in therange of 1 to 100 nm.

[0185] In the transparent conductive film, the hardcoat layer 1 isformed on the reverse side of the second polymer film 2 d provided withthe adhesive layer 9 as mentioned above to protect the polymer film fromthe load by input with a pen or fingertip. The hardcoat layer can beformed in the same manner as in the first invention.

[0186] Further the transparent conductive layer 2 c may be formeddirectly on the first polymer film 4, or formed through the undercoatlayer on the polymer film. The provision of the undercoat layer enhancesthe bonding strength to the polymer film to prevent the peeling of thetransparent conductive layer.

[0187] The undercoat layer can be formed by vapor deposition processusing the materials used for forming the protective layer. Otherwise, asthe undercoat layer, a layer of resin such as acrylic resin, urethaneresin or epoxy resin, or a layer of hydrolysis product of an organicsilicon compound can be formed by coating. The undercoat coated layercan be formed by applying a coating liquid having a desired compositiononto the polymer film using a coater such as bar coater.

[0188] The polymer film can be subjected to an appropriate surfacetreatment in the same manner as in the first invention before theundercoat layer is formed on the polymer film. The hardcoat layer can besubjected to an appropriate surface processing in the same manner as inthe first invention.

[0189] On the hardcoat layer, an antireflection layer can be formed.

[0190] The antireflection layer includes laminates having the followingstructures:

[0191] (a) a laminate of two layers in total composed of a highrefractive index-transparent thin layer and a low refractiveindex-transparent thin layer;

[0192] (b) a laminate of four layers in total that two high refractiveindex-transparent thin layers and two low refractive index-transparentthin layers are alternately provided one by one;

[0193] (c) a laminate of three layers in total composed of anintermediate refractive index-transparent thin layer, a low refractiveindex-transparent thin layer and a high refractive index-transparentthin layer;

[0194] (d) a laminate of six layers in total that three high refractiveindex-transparent thin layers and three low refractive index-transparentthin layers are alternately provided one by one.

[0195] Examples of materials of the above high or intermediaterefractive index-transparent thin layer include ITO (Indium Tin Oxide),ZnO, Al-doped ZnO, TiO₂, SnO₂, and ZrO whose films generally haverefractive index of 1.8 or more.

[0196] Examples of materials of the above low or intermediate refractiveindex-transparent thin layer include SiO₂, MgF₂, Al₂O₃, acrylic resin,urethane resin, silicone resin and fluorine resin whose films generallyhave refractive index of 1.6 or less. Otherwise, the thin layer can beobtained by coating of a paint comprising an organic binder and lowrefractive index-inorganic powders mentioned above.

[0197] The thicknesses of the low, intermediate and high refractiveindex-transparent thin layers are appropriately set depending upon thenumber of layers superposed and materials used in the layers and thecentral wavelength so as to lower the reflectivity in a visible rayregion by interference of light.

[0198] For example, in the case of the four-layered antireflectionlayer, it is preferred that a first high refractive index-thin layerprovided on the transparent plate side has thickness of 5 to 50 nm, asecond low refractive index-thin layer has thickness of 5 to 50 nm, athird high refractive index-thin layer has thickness of 50 to 100 nm,and a forth low refractive index-thin layer has thickness of 50 to 150nm. Further, an anti-contamination layer may be formed on theantireflection layer to improve resistance to contamination. Examples ofthe anti-contamination layer include a fluoric resin thin layer and asilicone resin thin layer having the thickness of 1 to 1,000 nm.

[0199] The antireflection layer can be also used in the first and secondinvention. The materials of the spacers can use those described in thefirst invention. The transparent conductive film can be employed in theuse of the first invention.

[0200] Subsequently, the embodiments of the forth invention areexplained in detail by referring FIG. 8 to FIG. 10.

[0201]FIG. 8 is a section view showing an example of the transparentconductive film of the forth invention according to the presentinvention. In FIG. 8, a hardcoat layer 1 is provided on one side of apolymer film 2, and an undercoat layer 3 is provided on the other sideof the polymer film 2, and further a first transparent conductive layer4 of a first metal oxide is formed on the undercoat layer 3 and a secondtransparent conductive layer 14 of a second metal oxide is formed on thefirst transparent conductive layer 4. The second transparent conductivelayer 14 is formed by vapor deposition under the condition differentfrom that of the vapor deposition in the formation of the firsttransparent conductive layer 4.

[0202] The first and second transparent conductive layers have the samecomponents constituting metal oxide as each other but are formed underdifferent conditions from each other. Examples of the metal oxidesinclude indium oxide-tin oxide (ITO), zinc oxide-aluminum oxide (ZAO),and antimony oxide-tin oxide (ATO).

[0203]FIG. 9 is a section view showing an example of the touch panelhaving the transparent conductive film of the invention. In the lowerelectrode, a first transparent conductive layer 4 b of a first metaloxide is provided on a polymer film 2 b through an undercoat layer 3 b,and a transparent plate 7 of a glass or plastic plate is bonded to theother side of the polymer film 2 b through an adhesive layer 6. Theupper electrode shown in FIG. 8 is bonded to the lower electrode throughdot spacers 5 such that the transparent conductive layers of the lowerand upper electrodes face each other to provide a touch panel.

[0204]FIG. 10 is a section view showing another example of the touchpanel having the transparent conductive film of the invention. A lowerelectrode is prepared by superposing directly the first transparentconductive layer 4 b of first metal oxide on a transparent plate 7 of aglass plate, and the lower electrode is bonded to the upper electrode,which comprising a hardcoat layer 1 a, a polymer film 2 a, first andsecond transparent conductive layers 4 a, 14 a, through dot spacers 5such that the transparent conductive layers of the lower and upperelectrodes face each other to provide a touch panel.

[0205] A process for preparing the transparent conductive layer usingmetal oxide is explained by taking an example of ITO film. ZAO and ATOfilms can be formed in the same manner.

[0206] The ITO film is preferably formed by sputtering process. In casea first and second ITO films are formed using sintered material of amixture of indium oxide-tin oxide as target material, the secondtransparent conductive layer is formed under different depositionconditions from that for forming the first transparent conductive layer,whereby the first and second transparent conductive layers havedifferent properties from each other.

[0207] The oxygen content of the second transparent conductive layer canbe enhanced compared with that of first transparent conductive layer by,for example, flowing more amount of oxygen in the sputtering processthan in the first transparent conductive layer. Further, the nitrogencontent of the second transparent conductive layer can be enhanced by,for example, flowing more amount of nitrogen in the sputtering processthan in the first transparent conductive layer. Furthermore, theroughness of surface of the ITO film can be enhanced by increasing thepressure or electric power in the sputtering process, wherebycrystallization state or surface shape can be varied between the firstand second transparent conductive layers. As mentioned above, in casethe first and second transparent conductive layers (ITO films) havedifferent properties from each other, the second ITO film of the upperelectrode is scarcely fused to the first ITO film of the lower electrodeto prevent the falling or peeling of the transparent conductive layerfrom the polymer film.

[0208] Naturally, the first ITO film may have increased oxygen ornitrogen content or increased roughness compared with the second ITOfilm. In this case, similarly, the second ITO film of the upperelectrode is different in the properties from the first ITO film of thelower electrode, and therefore the two layers are scarcely fused to eachother.

[0209] When the ITO film is excessively thin, the film does not showsufficient conductivity. When the ITO film is excessively thick, thefilm show extremely reduced resistivity to bring about a touch panel nothaving good response. Further this ITO film is costly prepared and hasincreased thickness. Thus the total thickness of the first and secondtransparent conductive layers preferably is in the range of 1 to 500 nm,especially 5 to 100 nm.

[0210] The ITO film of the lower electrode can be set to be the sameproperties as the first ITO film of the upper electrode but different inthe film properties from the second ITO film of the upper electrode,whereby the fusion between the ITO films can be prevented. Anytransparent plate on which an ITO film having the same properties as thefirst ITO film of the upper electrode is formed can be used as the lowerelectrode. For example, a glass plate on which an ITO film having thesame properties as the first ITO film of the upper electrode is directlyformed can be employed.

[0211] Although the ITO film is explained above, the first and secondtransparent conductive layers using ZAO or ATO can be also formed byvariation of the conditions of vapor deposition in the same manner asabove.

[0212] In the invention, the materials and thickness of the polymer film2, 2 a, 2 b follow the description in the first invention.

[0213] When the polymer film is used in the lower electrode of the touchpanel, the thickness of the polymer film may be in the range of 0.5 to 2mm that is thicker than the above range. However, the same thickness ofthe polymer film as that of the upper electrode can be also adopted inthe case of the combination of the polymer film with the transparentplate such as a plastic plate.

[0214] In case the transparent conductive film is used as the upperelectrode, a hardcoat layer can be formed on the reverse side having noITO film of the transparent conductive film to protect the polymer filmfrom the load by input of a pen or fingertip. Examples of the hardcoatlayer include an acrylic resin layer, an epoxy resin layer, a urethaneresin layer, and a silicone resin layer. The thickness generally is 1 to50 μm. The hardcoat layer may contain fine particles such as silicaparticles or alumina particles in the mixed condition. Further antiglareprocessing, in which scattering materials are kneaded, may be applied tothe hardcoat layer.

[0215] The antireflection layer can be formed on the hardcoat layer.Examples of the antireflection layer include a laminate composed of ahigh refractive index-transparent thin layer and a low refractiveindex-transparent thin layer.

[0216] Further, an anti-contamination layer may be formed on theantireflection layer provided on the hardcoat layer to improveresistance to contamination. Examples of the anti-contamination layerinclude a fluoric resin thin layer and a silicone resin thin layerhaving the thickness of 1 to 1,000 nm. Further the above antireflectionlayer may be provided.

[0217] The ITO film may be directly formed on the polymer film. However,the undercoat layer is generally provided between the polymer film andthe ITO film, whereby the bonding strength between the polymer film andthe ITO film can be enhanced to prevent the peeling of the transparentlayer.

[0218] Examples of materials of the undercoat layer include resins suchas acrylic resin, urethane resin, epoxy resin, and hydrolysis product ofan organic silicon compound.

[0219] The undercoat layer can be formed by applying a coating liquid ofan appropriate composition onto a polymer film with a coater such as adoctor knife coater, bar coater, gravure roll coater, curtain coater orknife coater.

[0220] The polymer film 2,2 a, 2 b can be subjected to an appropriatetreatment such as a plasma treatment, corona treatment orsolvent-washing treatment according to a conventional method, before theundercoat layer is formed on the polymer film, in order to enhance thebonding strength of the ITO layer to be formed.

[0221] Materials of the spacers include thermosetting resin,light-curable resin. The spacers are generally formed by printing theabove resin on the transparent conductive layer.

[0222] As materials of an adhesive layer for bonding the polymer film tothe transparent plate, epoxy resin, combination of phenol or urethaneresin with a hardener, or adhesive of acrylic type, rubber type orsilicon type is generally used.

[0223] Subsequently, the embodiments of the fifth invention areexplained in detail by referring FIG. 11 to FIG. 12.

[0224]FIG. 11 is a section view showing an example of the transparentconductive plate of the fifth invention according to the presentinvention. In the transparent conductive plate, a polymer film 2provided with a transparent conductive layer 4 through an adhesive layer9 is provided on a transparent plate 7, and spacers (micro dot spacers)5 are provided on the transparent conductive layer 4. The spacers areneeded when the lower electrode is bonded to an upper electrode toprepare a touch panel. The adhesive layer is a layer comprisingpolyolefin resin according to the invention. The adhesive layer absorbsforce (load) given to the transparent conductive layer to preventpeeling of the transparent conductive layer from the polymer film.Further, though the load generally brings about peeling between theadhesive layer and the polymer film or transparent plate (especiallyplastic plate), the adhesive layer of the invention is improved inbonding strength not to bring about the peeling. When the polyolefincrosslinked is used, the above effect is greatly enhanced.

[0225]FIG. 12 is a section view showing an example of the touch panel inwhich the transparent conductive plate the fifth invention is used inthe lower electrode. The transparent conductive plate in shown in FIG.11 is employed as a lower electrode. An upper electrode is composed of apolymer film 2 a, a hardcoat layer 1 provided on one side of the filmand a transparent conductive layer 4 a provided through an undercoatlayer 3 on the other side of the film. The lower and upper electrodesare bonded to each other by the adhesive layer to prepare the touchpanel of the invention. The adhesive layer 9 comprising polyolefin resinabsorbs force (load) applied from outside to the transparent conductivelayer to extremely reduce the load applied to the transparent conductivelayer, as shown in FIG. 12. The adhesive layer may be provided between ahardcoat layer (preferably polymer film having hardcoat layer) and thepolymer film 2 a.

[0226] The adhesive layer 9 of the invention comprises polyolefin resin,and has adequate modulus of elasticity and excellent adhesion. In case atouch panel provided with the transparent conductive plate as a lowerelectrode is repeatedly used, the adhesive layer relaxes the loadapplied to the transparent conductive layer (transparent electrode)whereby the excellent bonding strength between the layers is maintainedand satisfactory durability can be obtained. In more detail, theprovision of an adhesive layer enables the prevention of crack, fallingand peeling of the transparent conductive layer, which are brought aboutby repeatedly carrying out input with a pen or fingertip on the surfaceof the upper electrode. The protective layer may be provided on thesurface of the transparent conductive layer.

[0227] In the invention, the materials and thickness of the polymer film2, 2 a are as described in the first invention. The materials andthickness of the transparent conductive layer 4, 4 a also are asdescribed in the first invention.

[0228] The transparent conductive layer can be formed according to theconventional method, but preferably formed by sputtering process.

[0229] The transparent plate 7 is generally a plastic or glass plate.Preferred examples of materials of the plastic plate include acrylicresin (especially polymethyl methacrylate), polycarbonate resin,polystyrene resin, polyolefin resin and amorphous polyolefin resin. Thethickness is generally in the range of 50 μm to 0.5 mm.

[0230] In the invention, the transparent plate 7 is bonded to thereverse side of the polymer film 2 having the transparent conductivelayer 4 through the adhesive layer 9. The materials of the adhesivelayer 9 are as described in the third invention.

[0231] The adhesive layer of the invention is generally prepared in thesame manner as in the third invention, for example, by homogeneouslymixing a composition composed of the above-mentioned materials in anappropriate proportion, kneading the mixture using an extruder or roll,and subjecting the kneaded mixture to a film-forming process using acalendar, roll, T-die extrusion or inflation to form a film of apredetermined dimension. A more preferred process for forming theadhesive layer comprises the steps of: mixing and dissolvinghomogeneously the components for forming adhesive layer in a goodsolvent, applying the resultant solution onto a separator coated closelywith silicone or fluoric resin (or onto a support) by means offlow-coater process, roll-coater process, gravure-roll process,mayer-bar process or lip-die coating process, and vaporizing thesolvent. Then, the resultant layer is peeled from the support to obtainthe adhesive layer (uncrosslinked).

[0232] The transparent conductive plate of the invention can be obtainedby bonding the plastic plate or glass plate to the polymer film B havingthe transparent conductive layer using the above (crosslinkable)adhesive layer. The bonding (laminating) may be carried out usingcalendar process, roll process, T-die extrusion process or inflationprocess at the same time with the formation of the adhesive layer.Otherwise, these layers, films and plate can be bonded to each other bydepressing them under heating using a roll or the like. After thebonding, the resultant laminate is preferably subjected to a degassingtreatment by pressurizing and heating and to a degassing treatment byvacuum heating to remove gas in the adhesive layer. The degassingtreatment by pressurizing is carried out by placing the laminate in apressurizing and heating chamber such as an autoclave to remove the gas(degas). In case a crosslinkable adhesive is used as an adhesive, it iscrosslinked after the degassing.

[0233] Otherwise, the transparent conductive plate preferably isprepared by applying the materials for forming the adhesive layer ontothe surface having no transparent conductive layer of the polymer film,introducing the polymer film provided with a layer of the materials(adhesive layer) into a mold for molding such that the transparentconductive layer faces a surface of the mold, and injection molding aresin for forming a transparent plastic plate in the mold provided withthe polymer film to incorporate (unite) the polymer film and the resin.It is also possible to carry out crosslinking of the adhesive layer inthe forming process.

[0234] When the crosslinking is performed by heating, the temperaturefor the heating, depending on kinds of crosslinkers (organic peroxides)generally is in the range of 70 to 150° C., preferably 70 to 130° C.,for 10 sec. to 120 min., preferably 20 sec. to 60 min. When thecrosslinking is performed by light after the degassing, light source canbe adopted by selecting from a large number of sources emitting light inwavelength of ultraviolet to visible ray, for example, superhigh-pressure, high-pressure and low-pressure mercury lamps, a chemicallamp, a xenon lamp, a halogen lamp, a mercury halogen lamp, a carbon arclamp, and an incandescent electric lamp, and laser beam. The irradiation(exposing) time is generally a few seconds to a few minutes, dependingupon kinds of the lamp and strength of light. To promote the curing, thelaminate may be heated beforehand for 40 to 120° C., and then the heatedlaminate may be exposed to ultraviolet ray.

[0235] Further the pressure applied to the laminate when the bonding iscarried out by the adhesive layer is also set appropriately. Thepressure is generally in the range of 0 to 50 kg/cm², preferably 0 to 30kg/cm².

[0236] The protective layer can be provided on the transparentconductive layer. The protective layer descried previously can be usedin this case.

[0237] The protective layer can be formed on the transparent conductivelayer of the lower or upper electrode. In more detail, provision ofprotective layer on the transparent conductive layer of only oneelectrode, i.e., lower or upper electrode, brings about interruption ofthe affinity interaction between the transparent conductive layershaving the same or similar properties each other, whereby thetransparent conductive film can be improved in scratching resistance.

[0238] The transparent conductive film of the upper electrode describedpreviously can be also used in this case.

[0239] Subsequently, the embodiments of the sixth invention areexplained in detail by referring FIG. 13 to FIG. 14.

[0240]FIG. 13 is a section view showing an example of the touch panelhaving the transparent conductive film of the sixth invention. The touchpanel of the invention is composed of an upper electrode and a lowerelectrode. In the upper electrode, an undercoat layer 3 a and a firsttransparent conductive layer 4 a are superposed in this order on oneside of a polymer film 2 a whereas a hardcoat layer 1 a is provided onthe other side of the film 2 a. In the lower electrode, a silicon oxidelayer 13 and a second transparent conductive layer 7 a are superposed inthis order on a soda glass plate 17, and spacers 5 a are provided on thesecond transparent conductive layer 7 a. These upper and lowerelectrodes are arranged so as to be faced to each other and bonded toeach other on their circumferences using a belt-shaped adhesive layer 19a to prepare a touch panel.

[0241]FIG. 14 is a section view showing another example of the touchpanel using the transparent conductive film of the invention. Thestructure of the upper electrode is the same as that of the touch panelshown in FIG. 13. In the lower electrode, a polymer film 2 b is bondedto one side of a plastic plate 18 through an adhesive layer 19 b, and anundercoat layer 3 b and a second transparent conductive layer 4 b areprovided in this order on other side of the film, and further spacers 5a are formed on the second transparent conductive layer 4 b. These upperand lower electrodes are arranged so as to be faced to each other andbonded to each other on their circumferences using a belt-shapedadhesive layer 19 a to prepare a touch panel, in the same manner as inFIG. 13.

[0242] In the invention, the first and second transparent conductivelayers 4 a, 4 b are formed from materials different from each other.Examples of the materials include metal oxide, combination of the metaloxides, composite film consisting essentially of the metal oxide(s), andfurther gold, silver, nickel, aluminum, palladium. The materialsdifferent from each other mean those different from each other to theextent that is capable of interrupting physical or chemical affinitybetween the first and second transparent conductive layers. In case oneof the first and second transparent conductive layers uses metal oxide,the combination of metal oxides, composite film consisting essentiallyof the metal oxide(s) or metal material, the other transparentconductive layer uses the metal oxide, combination, composite film ormetal material different in at least one metal, the proportion or thefilm-forming conditions when the composition is the same as each other,from those in the former transparent conductive layer. For example, whenone of the first and second transparent conductive layers uses metaloxide (e.g., tin oxide), the other transparent conductive layer usesmetal oxide (e.g., indium oxide, zinc oxide, antimony oxide, cadmiumoxide), the combination of metal oxides (e.g., ITO, IZO, ATO, GZO),composite film consisting essentially of the metal oxide(s), or metalmaterial (e.g., gold, silver, nickel, aluminum, palladium). Otherwise,when one of the first and second transparent conductive layers uses thecombination of metal oxides (e.g., ITO), the other transparentconductive layer uses metal oxide (e.g., indium oxide, zinc oxide,antimony oxide, cadmium oxide), the combination of metal oxides (e.g.,IZO, ATO, GZO) different from said combination, the combination of metaloxides that has the same metal oxides as those of said combination butthe proportion of metal oxides different from that of said combination,composite film consisting essentially of the metal oxide(s) or metalmaterial (e.g., gold, silver, nickel, aluminum, palladium).

[0243] Preferred metal oxides include indium oxide, zinc oxide, tinoxide, antimony oxide and cadmium oxide, and especially tin oxide ispreferred from the viewpoint that a layer having high transparency canbe easily obtained.

[0244] Preferred combinations of metal oxides include sintered materialof indium oxide-tin oxide (ITO), sintered material of indium oxide-zincoxide (IZO), sintered material of antimony oxide-tin oxide (ATO), andgallium-doped zinc oxide (GZO). Especially ITO and IZO are preferredbecause these have high electrical conductivity. The combinations ofmetal oxides in the upper and lower electrodes can have the same metaloxides as each other but the proportion of metal oxides different fromeach other.

[0245] Examples of the composite film mainly consisting of the metaloxide(s) include films obtained by dispersing the above-mentioned metaloxides in binder resin such as acrylic resin, urethane resin or epoxyresin.

[0246] When a thickness of the transparent conductive layer, dependingupon the materials used therein, is too small, the transparentconductive layer cannot have sufficient conductivity. When the thicknessis too large, the transparent conductive layer cannot have reducedresistivity not to give good response of the resultant touch panel, andsuffers from increased cost for forming film and increased thickness ofthe transparent conductive film. Thus, the thickness of the transparentconductive layer preferably is in the range of 1 to 500 nm, especially 5to 100 nm

[0247] The transparent conductive layer can be formed by physical orchemical vapor deposition. Examples of the physical vapor depositioninclude vacuum metallizing process, sputtering process, ion-platingprocess, laser-ablation process. Examples of the chemical vapordeposition include atmospheric CVD process, decompression CVD process,and plasma CVD process.

[0248] The above-mentioned protective layer can be provided on thetransparent conductive layer to increase the film strength forprevention of falling or peeling of the transparent conductive layer.

[0249] In the lower electrode, the second transparent conductive layer 4b can be superposed on a soda glass plate through a silicon oxide layer13. The silicon oxide layer 13 is provided in order to prevent alkalicomponents contained in the soda glass from eluting. Further the secondtransparent conductive layer 4 b of the lower electrode may be bonded tothe plastic plate 18 made of acrylic resin or polycarbonate through theundercoat layer 3 b and the polymer film 2 b.

[0250] In the invention, the materials and thickness of the polymer film2 a, 2 b can use those described previously.

[0251] In case the polymer film is used in the lower electrode, thethickness of the polymer film can be set to the range more than theabove range, for example in the range of 0.5 to 2 mm. However, thepolymer film can also have the same thickness as in the upper electrodein the case of bonding the film to the plastic plate.

[0252] In the upper electrode of the touch panel of the invention, thehardcoat layer 1 a, 1 b can be formed on the reverse side (side havingno transparent conductive layer) of the transparent conductive layer 4a, 4 b of the polymer film 2 a, 2 b in order to protect the surface ofthe polymer film from damage by input with a pen or fingertip. Thehardcoat layer can use materials mentioned previously. Further, theantireflection layer mentioned previously may be provided on thehardcoat layer.

[0253] Further, a surface of the hardcoat layer 1 a can be processed byan antiglare processing, or an AR treatment for the purpose of theimprovement of optical characteristics.

[0254] Moreover, the transparent conductive layer may be directly formedon the polymer film. However, the undercoat layer 3 a, 3 b may beprovided between the polymer film 2 a, 2 b and the transparentconductive layer 4 a, 4 b, whereby the bonding strength between thepolymer film 2 a, 2 b and the transparent conductive layer 4 a, 4 b canbe enhanced to prevent the peeling of the transparent conductive layer 4a, 4 b.

[0255] The materials and process for forming the undercoat layer 3 a, 3b are as mentioned previously. The polymer film 2 a, 2 b may besubjected to plasma treatment, corona treatment or solvent washingtreatment as described previously.

[0256] Materials of the (dot) spacers include thermosetting resin,light-curable resin. The spacers are generally formed by printing theabove resin on the transparent conductive layer.

[0257] Materials of the adhesive layer 19 a, 19 b include acrylic resin,epoxy resin, phenol resin and silicone elastomer. When the thickness ofthe adhesive layer 19 a, 19 b bonding the upper electrode to the lowerelectrode is excessively thick, the pushing with a pen or fingertip doesnot bring about turning on electricity because an interval between theupper and lower electrodes is too increased, which makes it impossibleto input to the touch panel. Excessively reduced thickness of theadhesive layer leads to frequent occurrence of input error because asmall impact brings about turning on electricity. Hence the thicknesspreferably is in the range of 20 to 100 μm, especially 50 to 70 μm.

[0258] The transparent conductive film can be employed in uses describedpreviously.

EXAMPLE

[0259] The invention is illustrated in detail using the followingExamples.

Examples 1 to 3 and Comparison Example 1 First Invention

[0260] (1) Preparation of Samples

[0261] On a PET film having thickness of 188 μm, a hardcoat agent(Z7501, available from JSR Co., Ltd) was coated using a bar coater,dried at 100° C. for five minutes to form a hardcoat layer 1 a (beforecuring) having a dried thickness of 5 μm. The layer was exposed to ahigh-pressure mercury lamp (Irradiation strength: 80 mW/m², Integratingamount of light: 300 mJ/cm²) to cure. On the reverse side of the PETfilm, a coating liquid having a composition set forth in Table 1 wascoated using a bar coater, and dried at 100° C. for five minutes to forman undercoat layer (before curing) having a dried thickness of 5 μm. Thelayer was exposed to a high-pressure mercury lamp (Irradiation strength:80 mW/m², Integrating amount of light: 300 mJ/cm²) to cure.

[0262] Subsequently, ITO was placed as a target in a magnetron DCsputtering device, and the resultant PET film having the undercoat layerwas placed in a vacuum chamber and then pressure of the chamber wasreduced by a turbo molecular pump to 1×10⁻⁴ Pa. Thereafter, Ar gas of200 cc/min. and oxygen gas of 3 cc/min. were introduced into the chamberto adjust the chamber to 0.5 Pa, and then voltage was applied to the ITOtarget to form an ITO film having thickness of about 30 nm.

[0263] (2) Durability Test

[0264] An input pen (pen made of polyacetal; tip end: 0.8R) carryingload of 250 g thereon was repeatedly ground 100,000 times on thehardcoat layer (reverse side of the transparent conductive layer) of thefilm whereby a grinding test was carried out. Then, the electricalcharacteristics (electrical resistivity) of the film is determined andestimated as follows:

[0265] “◯ (Good)”: rate of change of the resistivity after the test tothat before the test is less than 30%;

[0266] “x (Poor)”: rate of change of the resistivity after the test tothat before the test is not less than 30%. TABLE 1 Example 1 Example 2Example 3 Com. Ex. 1 Resin Urethane acrylate*1) 100 100 100 100Composition Acrylate monomer*2)  5  5  5  5 (weight Photopolymerization 2  2  2  2 parts) initiator*3) Amino-containing  3 monomer*4)Amino-containing  3 monomer*5) Phosphoric  3 acid-containing monomer*6)Result of Change rate of 20% 23% 15% 35% Durability resistivity testEstimation ∘ ∘ ∘ x

[0267] Table 1 shows that the transparent conductive layer of theinvention is free from deterioration of electrical characteristics andshows excellent durability.

[0268] Hence, according to the first invention, the falling or peelingof the transparent conductive layer of the transparent conductive filmis effectively prevented by provision of the undercoat layer containinga compound having at least one group of amino and phosphoric acidgroups. Further by the transparent conductive film having the aboveundercoat layer, the touch panel having excellent durability can beobtained.

[Examples 4 to 7 and Comparison Example 2] Second Invention

[0269] (1) Preparation of Samples

[0270] On both sides of a PET film having thickness of 188 μm, ahardcoat agent (Z7501, available from JSR Co., Ltd) was coated using abar coater, dried at 100° C. for five minutes to form a hardcoat layer 1a and an undercoat layer 3 a (before curing) each having a driedthickness of 5 μm. The layer was exposed to a high-pressure mercury lamp(Irradiation strength: 80 mW/m², Integrating amount of light: 300mJ/cm²) to cure.

[0271] Subsequently, ITO was placed as a target in a magnetron DCsputtering device, and the resultant PET film having the undercoat layerwas placed in a vacuum chamber and then pressure of the chamber wasreduced by a turbo molecular pump to 5×10⁻⁴ Pa. Thereafter, a mixturegas of Ar gas of 196 sccm (flowing amount) and oxygen gas of 4 sccm(flowing amount) was introduced into the chamber to adjust the chamberto 0.5 Pa, and then voltage of 2 kw was applied to the ITO target toform an ITO thin layer having surface resistivity of 500 Ω/□ (sq). Aprotective layer comprising a compound set forth in Table 2 havingthickness set forth in Table 2 was formed on the ITO thin layer of thetransparent conductive film.

[0272] (Film Forming Process in Examples 4 and 5)

[0273] A mixture of the materials in Table 2 was coated on the ITO thinlayer using a bar coater, dried at 100° C. for five minutes to form aprotective layer having thickness set forth in Table 2. The protectivelayer was exposed to a high-pressure mercury lamp (Irradiation strength:80 mW/m², Integrating amount of light: 300 mJ/cm²) to cure.

[0274] (Film Forming Process in Examples 6 and 7)

[0275] A mixture of the materials in Table 2 was coated on the ITO thinlayer using a bar coater, dried at 80° C. for 30 minutes to form aprotective layer having thickness set forth in Table 2. The protectivelayer was allowed to stand at room temperature for seven days, and thensubjected to the durability test.

[0276] (2) Durability Test

[0277] An input pen (pen made of polyacetal; tip end: 0.8R) carryingload of 250 g thereon was repeatedly ground 100,000 times on thehardcoat layer (reverse side of the transparent conductive layer) of thefilm whereby a grinding test was carried out. Then, the electricalcharacteristics (electrical resistivity) of the film is determined andestimated as follows:

[0278] “◯ (Good)”: rate of change of the resistivity after the test tothat before the test is less than 30%;

[0279] “x (Poor)”: rate of change of the resistivity after the test tothat before the test is not less than 30%. TABLE 2 *Co. Ex. 4 Ex. 5 Ex.6 Ex. 7 Ex. 2 Resin Urethane acrylate*1) 100 100 Composition Acrylate  5 5 (weight monomer*2) parts) Photopolymerization  2  2 initiator*3)Amino-containing 100 100 alkoxy silane*4) Thickness (nm)  50 500  40 600Result of Change rate of 20% 14% 15% 10% 38% Durability resistivity testAppearance ο ο ο ο x Total judgment ∘ ∘ ∘ ∘ x

[0280] Table 2 shows that the transparent conductive layer of theinvention is free from deterioration of electrical characteristics andshows excellent durability.

[0281] Hence, according to the second invention, the falling or peelingof the transparent conductive layer of the transparent conductive filmis effectively prevented by provision of the protective layer comprisingpolymeric compound, and the touch panel having excellent durability canbe easily prepared.

Example 8 and Comparison Examples 3 and 4 Third Invention

[0282] (1) Preparation of Samples

[0283] On a PET (polyethylene terephthalate) film having thickness of125 μm, a UV-curable acrylic resin paint containing silica fineparticles was coated, and the layer was exposed to a high-pressuremercury lamp (Irradiation strength: 80 mW/m², Integrating amount oflight: 300 mJ/cm²) to cure. Thus, the PET film having hardcoat layer(second polymer film) was obtained.

[0284] Subsequently, a PET film having thickness of 38 μm was subjectedto plasma treatment under reduced pressure. The plasma treatment wascarried out for 10 minutes under the conditions of reduced pressure(13.3 Pa) and voltage of 100 W using high-frequency electrical source(13.56 MHz) while argon gas of 100 ml/min. was flowed. Thereafter, in amagnetron-sputtering device, silicon as target was sputtered onto thetreated surface of the PET film to form a thin layer (an undercoatlayer) of silicon compound having a thickness of 10 nm. Further, in themagnetron-sputtering device, tin oxides (10 wt. %)-containing ITO plateas target was sputtered onto the thin layer under the followingconditions to form a transparent conductive layer of ITO having athickness of 20 nm. Thus, the transparent conductive film was obtained.

[0285] The formation of the ITO layer by the magnetron-sputtering devicewas carried out for 60 seconds under the conditions of the amount offlowing argon of 50 cc/min., the amount of flowing oxygen of 3 cc/min.,reduced pressure of 0.6 Pa, DC electric power of 2 kW and the revolutionrate of the plate of 10 rpm.

[0286] Subsequently, a 15 weight % solution of ethylene/vinyl acetatecopolymer (Ultrasene 710, available from Toso Co., Ltd, content of vinylacetate: 28 weight %) in toluene was prepared. 0.5 weight % of1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2.0 weight % ofglycidyl methacrylate and 0.5 weight % ofγ-methacryloxypropyltrimethoxysilane, based on the ethylene/vinylacetate copolymer, were added to the solution, and sufficiently mixed.The resultant coating liquid was coated on the PET film (width: 250 mm;thickness: 125 μm) having hardcoat layer (5 μm) using a bar coater toform an adhesive layer.

[0287] Subsequently, the PET film having hardcoat layer and the adhesivelayer was superposed to the transparent conductive film (38 μm) throughthe adhesive layer, and heated at 130° C. under pressure of 10 kg/cm²for 10 minutes. Thus a transparent conductive film for a touch panel wasobtained.

[0288] The thermo-crosslinked EVA (ethylene/vinyl acetate copolymer)thermo-crosslinkable adhesive layer, which was prepared by heating underpressure as above, had modulus of elasticity of 4.5×10⁴ Pa.

Comparison Example 3

[0289] In Example 8, a transparent conductive film for a touch panel wasobtained in the same manner except that the resultant PET film havinghardcoat layer and the transparent conductive film were bonded to eachother using an adhesive layer of a crosslinked epoxy adhesive (modulusof elasticity of 2.5×10⁷ Pa).

Comparison Example 4

[0290] In Example 8, a transparent conductive film for a touch panel wasobtained in the same manner except that the PET film having hardcoatlayer and the transparent conductive film were bonded to each otherusing an adhesive layer of a crosslinked urethane adhesive (modulus ofelasticity of 2.5×10⁷ Pa).

[0291] (Durability Test)

[0292] An input pen (pen made of polyacetal; tip end: 0.8R) carryingload of 250 g thereon was repeatedly ground 100,000 times on thehardcoat layer (reverse side of the transparent conductive layer) of thefilm whereby a grinding test was carried out.

[0293] (1) Adhesion (Bonding Strength)

[0294] After the test, whether the PET film was peeled from the adhesivelayer was observed and estimated as follows:

[0295] “Good”: peeling was not observed;

[0296] “Poor”: peeling was apparently observed.

[0297] (2) Change Rate of Electrical Resistivity

[0298] After the test, the electrical characteristics (electricalresistivity) of the film was determined and estimated as follows:

[0299] “Good”: rate of change of the resistivity after the test to thatbefore the test is less than 50%;

[0300] “Poor”: rate of change of the resistivity after the test to thatbefore the test is not less than 50%. TABLE 3 Example 8 Com. Ex. 3 Com.Ex. 4 Change rate of resistivity Good Poor Poor Adhesion Good Poor Poor

[0301] Table 3 shows that the transparent conductive layer of theinvention is free from separation (peeling) between the PET film and theadhesive layer and deterioration of electrical characteristics and hencethe touch panel using transparent conductive layer as the upperelectrode also shows excellent durability

[0302] Thus, in the transparent conductive film and touch panelaccording to the invention, the falling or peeling of the transparentconductive layer of the transparent conductive film is effectivelyprevented even if input by a pen or fingertip was repeatedly carried outon the surface of the transparent conductive layer (upper electrode).Therefore in the film and the touch panel, the uniformity of electricalresistivity is maintained and hence excellent durability can beobtained.

Examples 9 to 12 and Comparison Example 5 Forth Invention

[0303] On one side of a PET film having thickness of 188 μm, a hardcoatlayer of a thickness of 5 μm was formed by coating method using asolvent. The resultant film was cut to a size of 100×100 mm, and thesurface having no hardcoat layer of the film was subjected to plasmatreatment under reduced pressure. The plasma treatment was carried outfor 10 minutes under the conditions of reduced pressure (13.3 Pa) andvoltage of 100 W using high-frequency electric source (13.56 MHz) whileargon gas of 100 ml/min. was flowed.

[0304] Subsequently, in the magnetron-sputtering device, tin oxide (10wt. %)-containing ITO target was sputtered onto the treated surfaceunder the conditions of the amount of flowing argon of 50 ml/min. andthe amount of flowing oxygen of 2 ml/min. to form a transparentconductive layer of ITO having a thickness of 20 nm. Further, on the ITOlayer (thin layer), another ITO layer was formed using the abovemagnetron-sputtering device and the target material under the conditions(shown in Table 4) different from those in the formation of the aboveITO thin layer. Another ITO thin layer had different properties from theformer ITO thin layer.

[0305] A lower electrode was prepared as follows:

[0306] ITO was placed as a target in a magnetron DC sputtering device,and a soda glass plate having thickness of 1.1 mm was placed in a vacuumchamber, and then pressure of the chamber was reduced by a turbomolecular pump to 5×10⁻⁴ Pa. Thereafter, a mixture gas of Ar gas of 196sccm (flowing amount) and oxygen gas of 4 sccm (flowing amount) wasintroduced into the chamber to adjust the pressure of the chamber to 0.5Pa, and then voltage of 4 kw was applied to the ITO target to form anITO thin layer having surface resistivity of 500 Ω/□ (sq). Dot spacerswere printed on the ITO thin layer and cured to form the lowerelectrode.

[0307] The above transparent conductive film was used as an upperelectrode, and the upper and lower electrodes were subjected to etchingtreatment to form the electrodes having predetermined shape. Lead wiringwas formed on the edges of the upper and lower electrodes using Agpaste. The upper and lower electrodes were arranged such that both ofthe transparent conductive layers were faced to each other and theelectrodes were bonded to each other on the circumferences using anadhesive to prepare a touch panel. The thickness of the adhesive layerwas 60 μm.

[0308] (Durability Test)

[0309] Subsequently, the resultant films were subjected to durabilitytest by grinding writing. An input pen carrying load of 250 g thereonwas repeatedly ground 100,000 times on the film whereby a grinding testwas carried out. After the test, the electrical characteristics(electrical resistivity) of the film was determined and the durabilitywas estimated as follows:

[0310] “OK”: rate of change of the resistivity after the test to thatbefore the test is less than 50%;

[0311] “NG”: rate of change of the resistivity after the test to thatbefore the test is not less than 50%.

[0312] The results were shown in Table 4.

Comparison Example 5

[0313] In Example 9, a transparent conductive film for a touch panel wasobtained in the same manner except that the transparent conductive filmhad only one ITO thin layer.

[0314] The formation of the one ITO film by the magnetron-sputteringdevice was carried out under the conditions of the amount of flowingargon of 50 cc/min., the amount of flowing oxygen of 3 cc/min., reducedpressure of 0.5 Pa, DC electric power of 2 kW, and film-forming time of60 sec. under the condition of the revolution rate of the plate of 10rpm. TABLE 4 Difference DC between Electric Amount Amount Amount thelower Pressure Power of Ar of O₂ of N₂ Thickness and upper (Pa) (W)(ml/min) (ml/min) (ml/min) (nm) ITOs Durability Ex. 9 0.5  2 kW 50 10 —10 O₂*1) OK Ex. 10 0.5  2 kW 50  3 5 10 N₂*2) OK Ex. 11 4.0  2 kW 50  3— 10 Roughness*3) OK Ex. 12 0.5 10 kW 50  3 — 10 Roughness*3) OK Co. Ex.5 — — — — — — — NG

[0315] As apparent from above, in the formation of the transparentconductive layer of the upper electrode, the provision of a usual metaloxide layer and another metal oxide layer different in the compositionor surface shape (surface roughness) from the usual metal oxide layer onthe usual metal oxide layer according to the invention brings about atransparent conductive film in which falling and peeling from theelectrode can be prevented and fusing between the upper and lowerelectrodes can be prevented, and which has good grinding resistance andexcellent durability.

Examples 13 to 16 and Comparison Example 6 Forth Invention Similarly

[0316] On one side of a PET film having thickness of 188 μm, a hardcoatlayer of a thickness of 5 μm was formed by coating method using asolvent. The resultant film was cut to a size of 100×100 mm, and thesurface having no hardcoat layer of the film was subjected to plasmatreatment under reduced pressure. The plasma treatment was carried outfor 10 minutes under the conditions of reduced pressure (13.3 Pa) andvoltage of 100 W using high-frequency electric source (13.56 MHz) whileargon gas of 100 ml/min. was flowed.

[0317] Subsequently, in the magnetron-sputtering device, aluminum oxide(2 wt. %)-containing ZAO target was sputtered onto the treated surfaceunder the conditions of the amount of flowing argon of 50 ml/min. andthe amount of flowing oxygen of 2 ml/min. to form a transparentconductive layer of ZAO having a thickness of 20 nm. Further, on the ZAOlayer (thin film), another ZAO layer was formed using the abovemagnetron-sputtering device and the target material under the conditions(shown in Table 5) different from those in the formation of the aboveZAO thin layer. The latter ZAO thin layer had different properties fromthe former ZAO thin layer.

[0318] A lower electrode was prepared as follows:

[0319] ZAO was placed as a target in a magnetron DC sputtering device,and a soda glass plate having thickness of 1.1 mm was placed in a vacuumchamber, and then pressure of the chamber was reduced by a turbomolecular pump to 5×10⁻⁴ Pa. Thereafter, a mixture gas of Ar gas of 196sccm (flowing amount) and oxygen gas of 4 sccm (flowing amount) wasintroduced into the chamber to adjust the pressure of the chamber to 0.5Pa, and then voltage of 4 kw was applied to the ZAO target to form anZAO thin layer having surface resistivity of 500 Ω/□ (sq). Dot spacerswere printed on the ZAO thin layer and cured to form the lowerelectrode.

[0320] The above transparent conductive film was used as an upperelectrode, and the upper and lower electrodes were subjected to etchingtreatment to form the electrodes having predetermined shape. Lead wiringwas formed on the edges of the upper and lower electrodes using Agpaste. The upper and lower electrodes were arranged such that both ofthe transparent conductive layers were faced to each other and theelectrodes were bonded to each other on the circumferences using anadhesive to prepare a touch panel. The thickness of the adhesive layerwas 60 μm.

[0321] (Durability Test)

[0322] Subsequently, the resultant films were subjected to durabilitytest by grinding writing. An input pen carrying load of 250 g thereonwas repeatedly ground 100,000 times on the film, and thus a grindingtest was carried out. After the test, the electrical characteristics(electrical resistivity) of the film was determined and the durabilitywas estimated as follows:

[0323] “OK”: rate of change of the resistivity after the test to thatbefore the test is less than 50%;

[0324] “NG”: rate of change of the resistivity after the test to thatbefore the test is not less than 50%.

[0325] The results were shown in Table 5.

Comparison Example 6

[0326] In Example 13, a transparent conductive film for a touch panelwas obtained in the same manner except that the transparent conductivefilm had only one ZAO thin layer.

[0327] The formation of the one ZAO film by the magnetron-sputteringdevice was carried out under the conditions of the amount of flowingargon of 50 cc/min., the amount of flowing oxygen of 3 cc/min., reducedpressure of 0.5 Pa, DC electric power of 2 kW, and film-forming time of60 sec. under the condition of the revolution rate of the plate of 10rpm. TABLE 5 Difference DC between Electric Amount Amount Amount thelower Pressure Power of Ar of O₂ of N₂ Thickness and upper (Pa) (W)(ml/min) (ml/min) (ml/min) (nm) ZAOs Durability Ex. 13 0.5  2 kW 50 10 —10 O₂*1) OK Ex. 14 0.5  2 kW 50  3 5 10 N₂*2) OK Ex. 15 4.0  2 kW 50  3— 10 Roughness*3) OK Ex. 16 0.5 10 kW 50  3 — 10 Roughness*3) OK Co. Ex.6 — — — — — — — NG

[0328] As apparent from above, the invention facilitates the control ofthe thickness and resistivity of the transparent conductive film.Further, in the formation of the transparent conductive layer of theupper electrode, the provision of a ZAO layer and another metal oxidelayer different in the composition or surface shape (surface roughness)from the former ZAO layer on the former ZAO layer according to theinvention brings about a transparent conductive film in which fallingand peeling from the electrode and fusing between the upper and lowerelectrodes can be prevented, and which has good grinding resistance andexcellent durability.

Examples 17 to 20 and Comparison Example 7 Forth Invention Similarly

[0329] On one side of a PET film having thickness of 188 μm, a hardcoatlayer of a thickness of 5 μm was formed by coating method using asolvent. The resultant film was cut to a size of 100×100 mm, and thesurface having no hardcoat layer of the film was subjected to plasmatreatment under reduced pressure. The plasma treatment was carried outfor 10 minutes under the conditions of reduced pressure (13.3 Pa) andvoltage of 100 W using high-frequency electric source (13.56 MHz) whileargon gas of 100 ml/min. was flowed.

[0330] Subsequently, in the magnetron-sputtering device, antimony oxide(10 wt. %)-containing ATO target was sputtered onto the treated surfaceunder the conditions of the amount of flowing argon of 50 ml/min. andthe amount of flowing oxygen of 2 ml/min. to form a transparentconductive layer of ATO having a thickness of 20 nm. Further, on the ITOlayer (thin film), another ITO layer was formed using the abovemagnetron-sputtering device and materials under the conditions (shown inTable 6) different from those in the formation of the above ATO thinlayer. The latter ATO thin layer had different properties from theformer ATO thin layer.

[0331] A lower electrode was prepared as follows:

[0332] ATO was placed as a target in a magnetron DC sputtering device,and a soda glass plate having thickness of 1.1 mm was placed in a vacuumchamber and then pressure of the chamber was reduced by a turbomolecular pump to 5×10⁻⁴ Pa. Thereafter, a mixture gas of Ar gas of 196sccm (flowing amount) and oxygen gas of 4 sccm (flowing amount) wasintroduced into the chamber to adjust the pressure of the chamber to 0.5Pa, and then voltage of 4 kw was applied to the ATO target to form anATO thin layer having surface resistivity of 500 Ω/□ (sq). Dot spacerswere printed on the ATO thin layer and cured to form the lowerelectrode.

[0333] The above transparent conductive film was used as an upperelectrode, and the upper and lower electrodes were subjected to etchingtreatment to form the electrodes having predetermined shape. Lead wiringwas formed on the edges of the upper and lower electrodes using Agpaste. The upper and lower electrodes were arranged such that both ofthe transparent conductive layers were faced to each other and theelectrodes were bonded to each other on the circumferences using anadhesive to prepare a touch panel. The thickness of the adhesive layerwas 60 μm.

[0334] (Durability Test)

[0335] Subsequently, the resultant films were subjected to durabilitytest by grinding writing. An input pen carrying load of 250 g thereonwas repeatedly ground 100,000 times on the film, and thus a grindingtest was carried out. After the test, the electrical characteristics(electrical resistivity) of the film was determined and the durabilitywas estimated as follows:

[0336] “OK”: rate of change of the resistivity after the test to thatbefore the test is less than 50%;

[0337] “NG”: rate of change of the resistivity after the test to thatbefore the test is not less than 50%.

[0338] The results were shown in Table 6.

Comparison Example 7

[0339] In Example 17, a transparent conductive film for a touch panelwas obtained in the same manner except that the transparent conductivefilm had only one ATO thin layer.

[0340] The formation of the one ATO film by the magnetron-sputteringdevice was carried out under the conditions of the amount of flowingargon of 50 cc/min., the amount of flowing oxygen of 3 cc/min., reducedpressure of 0.5 Pa, DC electric power of 2 kW, and film-forming time of60 sec. under the condition of the revolution rate of the plate of 10rpm. TABLE 6 Difference DC between Electric Amount Amount Amount thelower Pressure Power of Ar of O₂ of N₂ Thickness and upper (Pa) (W)(ml/min) (ml/min) (ml/min) (nm) ATOs Durability Ex. 17 0.5  2 kW 50 10 —10 O₂*1) OK Ex. 18 0.5  2 kW 50  3 5 10 N₂*2) OK Ex. 19 4.0  2 kW 50  3— 10 Roughness*3) OK Ex. 20 0.5 10 kW 50  3 — 10 Roughness*3) OK Co. Ex.7 — — — — — — — NG

[0341] As apparent from above, the invention facilitates the control ofthe thickness and resistivity of the transparent conductive film.Further, in the formation of the transparent conductive layer of theupper electrode, the provisions of a ATO layer and another metal oxidelayer different in the composition or surface shape (surface roughness)from the former ATO layer on the former ATO layer according to theinvention bring about a low-priced transparent conductive film in whichfalling and peeling from the electrode and fusing between the upper andlower electrodes can be prevented, and which has good grindingresistance and excellent durability.

Examples 21 and Comparison Example 8 Fifth Invention

[0342] (1) Preparation of Samples

[0343] A surface of a PET film having thickness of 38 μm was subjectedto plasma treatment for 10 minutes under the conditions of reducedpressure (13.3 Pa) and voltage of 100 W using high-frequency electricsource (13.56 MHz) while argon gas of 100 ml/min. was flowed.Thereafter, in a magnetron-sputtering device, silicon as target wassputtered onto the treated surface of the PET film to form a thin layer(an undercoat layer) of silicon compound having a thickness of 10 nm.Further, in the magnetron-sputtering device, tin oxides (10 wt.%)-containing ITO plate as target was sputtered onto the thin layerunder the following conditions to form a transparent conductive layer ofITO having a thickness of 20 nm. Thus, the transparent conductive filmwas obtained.

[0344] The formation of the ITO layer by the magnetron-sputtering devicewas carried out for 60 seconds under the conditions of the amount offlowing argon of 50 cc/min., the amount of flowing oxygen of 3 cc/min.,reduced pressure of 0.5 Pa, DC electric power of 2 kW and the revolutionrate of the plate of 10 rpm.

[0345] Subsequently, a 15 weight % solution of ethylene/vinyl acetatecopolymer (Ultrasene 710, available from Toso Co., Ltd, content of vinylacetate: 28 weight %) in toluene was prepared. 0.5 weight % of1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2.0 weight % ofglycidyl methacrylate and 0.5 weight % ofγ-methacryloxypropyltrimethoxysilane, based on the ethylene/vinylacetate copolymer, were added to the solution, and sufficiently mixed.The resultant coating liquid was coated on the surface having notransparent conductive layer, and the PET film was placed in a injectionmolding machine such that the transparent conductive layer is faced tothe mold surface of the molding machine, and then PMMA (polymethylmethacrylate) resin was injected into the molding machine and maintainedat 130° C. for five minutes to be taken out. Thus a transparentconductive plate for touch panel was obtained.

[0346] The thermo-crosslinked EVA (ethylene/vinyl acetate copolymer)thermo-crosslinkable adhesive layer, which was crosslinked by heating asabove, had modulus of elasticity of 4.5×10⁴ Pa.

Comparison Example 8

[0347] In Example 21, a transparent conductive plate for touch panel wasobtained in the same manner except that the PMMA resin (plate) and thetransparent conductive film were bonded to each other by a crosslinkedadhesive layer of urethane adhesive (modulus of elasticity of 2.5×10⁷Pa).

[0348] (Durability Test)

[0349] The transparent conductive film as a upper electrode wassuperposed on the transparent conductive plate, and was subjected to thefollowing grinding writing test.

[0350] An input pen (pen made of polyacetal; tip end: 0.8R) carryingload of 250 g thereon was repeatedly ground 100,000 times on the surfaceof the transparent conductive layer.

[0351] (1) Adhesion (Bonding Strength)

[0352] After the test, whether the PET film was peeled from the adhesivelayer was observed and estimated as follows:

[0353] “Good”: peeling was not observed;

[0354] “Poor”: peeling was apparently observed.

[0355] (2) Change Rate of Electrical Resistivity

[0356] After the test, the electrical characteristics (electricalresistivity) of the film was determined and estimated as follows:

[0357] “Good”: rate of change of the resistivity after the test to thatbefore the test is less than 50%;

[0358] “Poor”: rate of change of the resistivity after the test to thatbefore the test is not less than 50%. TABLE 7 Example 21 Com. Ex. 8Change rate of resistivity Good Poor Adhesion Good Poor

[0359] Table 7 shows that the transparent conductive plate of theinvention has excellent durability because there is no separation(peeling) between the PET film and the adhesive layer even if is usedfor long-term and there is no deterioration of electricalcharacteristics after the grinding test, and hence a touch panel usingthe plate as a lower electrode also has excellent durability. In orderto compare in impact resistance a commercially available transparentconductive plate (comparison example 8) prepared by bonding atransparent conductive film to a glass plate with the plastic plate ofExample 21, both of the plates were allowed to fallen on a surface ofconcrete from height of 1 m. As a result, only the commerciallyavailable plate was broken. Further the plate showed poor durability inthe test durability.

[0360] Hence, in the transparent conductive plate and touch panel havingthis plate according to the invention, the falling or peeling of thetransparent conductive layer of the transparent conductive film scarcelyoccur even if input by a pen or fingertip was repeatedly carried out onthe surface of the transparent conductive layer (upper electrode) andtherefore the uniformity of electrical resistivity is maintained andhence excellent durability can be obtained.

Examples 22 and 23 and Comparison Examples 9 and 10 Sixth Invention

[0361] (1) Process for Preparing Electrodes

[0362] (a) Upper Electrode 1

[0363] ITO was set as a target in a magnetron DC sputtering device, anda PET film having thickness of 188 μm whose one side was coated with aUV-curable acrylate type hardcoat was set in a vacuum chamber.Subsequently, the pressure of the vacuum chamber was reduced by a turbomolecular pump to 5×10⁻⁴ Pa, and then a mixture gas of Ar gas of 196sccm (flowing amount) and oxygen gas of 4 sccm (flowing amount) wasintroduced into the vacuum chamber to adjust the pressure of the chamberto 0.5 Pa. Thereafter, voltage of 4 kw was applied to the ITO target toform an ITO thin layer having surface resistivity of 500 Ω/□ (sq) on theside having no hardcoat of the PET film.

[0364] (b) Upper Electrode 2

[0365] IZO was set as a target in a magnetron DC sputtering device, anda PET film having thickness of 188 μm whose one side was coated with aLV-curable acrylate type hardcoat was set in a vacuum chamber.Subsequently, the pressure of the vacuum chamber was reduced by a turbomolecular pump to 5×10⁻⁴ Pa, and then a mixture gas of Ar gas of 196sccm (flowing amount) and oxygen gas of 4 sccm (flowing amount) wasintroduced into the vacuum chamber to adjust the pressure of the vacuumchamber to 0.5 Pa. Thereafter, voltage of 4 kw was applied to the IZOtarget to form an IZO thin layer having surface resistivity of 500 Ω/□(sq) on the side having no hardcoat of the PET film.

[0366] (c) Lower Electrode 1

[0367] ITO was set as a target in a magnetron DC sputtering device, anda soda glass having a thickness of 1.1 mm whose both sides were providedwith a silicon oxide layer by dipping method was set in a vacuumchamber. Subsequently, the pressure of the device was reduced by a turbomolecular pump to 5×10⁻⁴ Pa, and then a mixture gas of Ar gas of 196sccm (flowing amount) and oxygen gas of 4 sccm (flowing amount) wasintroduced into the vacuum chamber to adjust the pressure of the vacuumchamber to 0.5 Pa. Thereafter, voltage of 4 kw was applied to the ITOtarget to form an ITO thin layer having surface resistivity of 1,000 Ω/□(sq) on the side having no hardcoat of the glass. Dot spacers wereprinted on the ITO thin layer and cured.

[0368] (d) Lower Electrode 2

[0369] IZO was set as a target in a magnetron DC sputtering device, anda soda glass having a thickness of 1.1 mm whose both sides were providedwith a silicon oxide layer by dipping method was set in a vacuumchamber. Subsequently, the pressure of the device was reduced by a turbomolecular pump to 5×10⁻⁴ Pa, and then a mixture gas of Ar gas of 196sccm (flowing amount) and oxygen gas of 4 sccm (flowing amount) wasintroduced into the vacuum chamber to adjust the pressure of the vacuumchamber to 0.5 Pa. Thereafter, voltage of 4 kw was applied to the IZOtarget to form an IZO thin layer having surface resistivity of 1,000 Ω/□(sq) on the side having no hardcoat of the glass. Dot spacers wereprinted on the ITO thin layer and cured.

[0370] (2) Process for Preparing Touch Panel

[0371] The upper and lower electrodes were subjected to etchingtreatment to form the electrodes having predetermined shape. Lead wiringwas formed on the edges of the upper and lower electrodes using Agpaste. The upper and lower electrodes were arranged such that both ofthe transparent conductive layers were faced to each other and theelectrodes were bonded to each other on the circumferences using anadhesive to prepare a touch panel. The thickness of the adhesive layerwas 60 μm.

[0372] (3) Estimation

[0373] Durability Test

[0374] An input pen (pen made of polyacetal; tip end: 0.8R) carryingload of 250 g thereon was repeatedly ground 100,000 times on thehardcoat layer (reverse side of the transparent conductive layer) of thefilm whereby a grinding test was carried out. Then, the electricalcharacteristics (electrical resistivity) of the film is determined andestimated as follows:

[0375] “◯ (Good)”: linearity after the test is less than 0.5%;

[0376] “x (Poor)”: linearity after the test is not less than 30%.

[0377] Further, the appearance of the film is estimated as follows:

[0378] “◯ (Good)”: there is no difference between appearance after thetest and that before the test;

[0379] “x (Poor)”: there is difference between appearance after the testand that before the test.

[0380] The linearity is index indicating the uniformity of resistivityof the transparent conductive layer. It can be determined as follows:Terminals of silver paste are formed on two sides of the upper and lowerelectrodes faced to each other, and direct current is applied betweenboth of the terminals. The linearity is defined in the followingequation:

Linearity (%)=|(I/L−v/V)|×100

[0381] In which L is that the distance between both of the electrodesand V is the applied voltage, and, under these conditions, I is thedistance from an optional point of the transparent conductive layer to aminus terminal, and v is potential difference between the point and theminus terminal. The linearity the smaller, more excellent is theuniformity of resistivity of the transparent conductive layer, and thelinearity of 0% represents compete uniformity of the resistivity. Theanalog-type touch panel according to usual resistance sensitive systempreferably has the linearity of not more than 1.5%.

[0382] (4) Examples and Comparison Examples

Example 22

[0383] A touch panel was prepared by using the upper electrode 1 and thelower electrode 2.

Example 23

[0384] A touch panel was prepared by using the upper electrode 2 and thelower electrode 1.

Comparison Example 9

[0385] A touch panel was prepared by using the upper electrode 1 and thelower electrode 1.

Comparison Example 10

[0386] A touch panel was prepared by using the upper electrode 2 and thelower electrode 2.

[0387] (5) The obtained results were shown in Table 8. TABLE 8 Example22 Example 23 Com. Ex. 9 Com. Ex. 10 Result of Durability Linearity 1.0%0.8% 15.5% 17.0% test Appearance ∘ ∘ x x Synthetic judgment ∘ ∘ x x

[0388] As apparent from above, according to the invention, physical andchemical affinity between the upper and lower electrodes is interruptedby the use different materials in the transparent conductive layer ofthe upper and lower electrodes and hence the falling or peeling of thetransparent conductive layer of the transparent conductive film iseffectively prevented. Thus, the touch panel which is free fromdeterioration of electrical characteristics and shows excellentdurability and further can be easily prepared, can be obtained.

[0389] [Description of Reference Number]

[0390]1, 1 a, 1 b: hardcoat layer

[0391]2, 2 a, 2 b, 2 c, 2 d: polymer film

[0392]3, 3 a, 3 b: undercoat layer

[0393]4, 4 a, 4 b, 14, 14 a: transparent conductive layer

[0394]5, 5 a, 5 b: spacers

[0395]6: adhesive layer

[0396]7: transparent plate

1. A transparent conductive film comprising a polymer film, an undercoatlayer and a transparent conductive layer which are superposed in thisorder, wherein the undercoat layer contains a compound having at leastone selected from an amino group and a phosphoric acid group.
 2. Atransparent conductive film as defined in claim 1, wherein thetransparent conductive layer comprises at least one compound selectedfrom indium oxide, tin oxide, zinc oxide, indium oxide-tin oxide (ITO),antimony oxide-tin oxide (ATO) and zinc oxide-aluminum oxide (ZAO).
 3. Atransparent conductive film as defined in claim 1 or 2, wherein ahardcoat layer is provided on a surface having no transparent conductivelayer of the polymer film.
 4. A transparent conductive film as definedin claim 1, wherein the compound having amino group is derived from acompound selected from dialkylaminoalkyl methacrylate and asilane-coupling agent having an amino group, and the compound havingphosphoric acid group is derived from a compound selected from2-methacryloyloxyethyl phosphate and dipehnyl-2-methacryloyloxyethylphosphate.
 5. A transparent conductive film as defined claim 1, whereinthe polymer film comprises polyethylene terephthalate.
 6. A transparentconductive film as defined in claim 1, wherein a protective layercomprising a polymeric compound is provided on the transparentconductive layer.
 7. A transparent conductive film as defined in claim6, wherein the polymeric compound is a resin composition containing atleast one resin selected from acrylic resin, polyester resin, epoxyresin, urethane resin, phenol resin, maleic acid resin, melamine resin,urea resin, polyimide resin and silicon-containing resin.
 8. Atransparent conductive film as defined in claim 6 or 7, wherein theprotective layer comprises a film formed by curing amino-containingalkoxy-silane.
 9. A transparent conductive film as defined in claim 6,wherein the protective layer comprises a film formed by curingUV-curable resin.
 10. A transparent conductive film as defined in claim1, which comprises the polymer film having the transparent conductivelayer thereon through the undercoat layer and another polymer filmhaving a hardcoat layer thereon, the two polymer films being bonded toeach other through an adhesive layer comprising polyolefin resin suchthat a surface having no transparent conductive layer of the polymerfilm and a surface having no hardcoat layer of another polymer film faceeach other.
 11. A transparent conductive film as defined in claim 10,wherein the polyolefin resin of the adhesive layer comprises copolymerof ethylene and vinyl acetate and/or (meth)acrylate.
 12. A transparentconductive film as defined in claim 10, wherein the polyolefin resin ofthe adhesive layer comprises a film formed by curing copolymer ofethylene and vinyl acetate and/or (meth)acrylate.
 13. A transparentconductive film as defined in claim 1, wherein the transparentconductive layer comprises a first transparent conductive layercomprising a first metal oxide and a second transparent conductive layercomprising a second metal oxide, and the second transparent conductivelayer is formed under the condition different from the condition forforming the first transparent conductive layer.
 14. A transparentconductive film as defined in claim 13, wherein the first and secondtransparent conductive layers comprise indium oxide-tin oxide (ITO),zinc oxide-aluminum oxide (ZAO) or antimony oxide-tin oxide (ATO).
 15. Atransparent conductive film as defined in claim 13 or 14, wherein thefirst and second transparent conductive layers are formed by a vapordeposition process selected from a sputtering process and a reactivesputtering process.
 16. A transparent conductive film as defined inclaim 15, wherein target material used in the vapor deposition processis a ceramic target formed by sintering mixed metal oxides or an alloytarget made of metal oxide.
 17. A transparent conductive film as definedin claim 13, wherein the second transparent conductive layer comprisingthe second metal oxide is different from the first transparentconductive layer comprising the first metal oxide in at least oneselected from oxygen content, nitrogen content, crystalline state andsurface shape.
 18. A transparent conductive film as defined in claim 17,wherein the condition for forming the second transparent conductivelayer comprising the second metal oxide by a sputtering process isdifferent in pressure and deposition rate in the sputtering from thatfor forming the first transparent conductive layer comprising the firstmetal oxide.
 19. A touch panel comprising an upper electrode having ahard coat layer, a first polymer film, a first undercoat layer and afirst transparent conductive layer superposed in this order, and a lowerelectrode having a plastic or glass plate, a second polymer film, asecond undercoat layer and a second transparent conductive layersuperposed in this order, the upper electrode and the lower electrodebeing bonded to each other through spacers such that both of thetransparent conductive layers face each other, wherein the upperelectrode and/or the lower electrode includes the transparent conductivefilm as defined in claim
 1. 20. A touch panel as defined in claim 19,wherein the lower electrode has a transparent plate, an adhesive layer,a polymer film and a second transparent conductive layer superposed inthis order, and the adhesive layer comprises polyolefin resin.
 21. Atouch panel as defined in claim 19 or 20, wherein the first transparentconductive layer of the upper electrode is formed from materialdifferent from that of the second transparent conductive layer of thelower electrode.
 22. A touch panel as defined in claim 21, wherein thefirst transparent conductive layer and the second transparent conductivelayer are a film of metal oxide, a film of combination of two or moremetal oxides or a composite film consisting essentially of metal oxide,or a film comprising gold, copper, nickel, aluminum or palladium.
 23. Atransparent conductive film having a polymer film and a transparentconductive layer provided thereon, wherein a protective layer comprisinga polymeric compound is formed on the transparent conductive layer. 24.A transparent conductive film comprising a polymer film having atransparent conductive layer provided thereon, and another polymer filmhaving a hard coat layer provided thereon, the two polymer films beingbonded to each other through an adhesive layer comprising polyolefinsuch that two surfaces having no layer of the two polymer films faceeach other.
 25. A transparent conductive plate comprising a transparentplate, an adhesive layer, a polymer film and a transparent conductivelayer superposed in this order, and the adhesive layer comprisespolyolefin resin.
 26. A process for the preparation of a transparentconductive plate as defined in claim 25, comprising the steps of:applying a material for forming an adhesive layer onto a surface havingno transparent conductive layer of a polymer film provided with thetransparent conductive layer, introducing the polymer film provided withthe adhesive layer into a mold for molding such that the transparentconductive layer faces a surface of the mold and injection molding aresin for forming a transparent plastic plate in the mold provided withthe polymer film to incorporate the polymer film and the resin.
 27. Atransparent conductive film comprising a polymer film and a transparentconductive layer comprising metal oxide formed thereon by a vapordeposition process, wherein the transparent conductive film comprises afirst transparent conductive layer comprising a first metal oxide and asecond transparent conductive layer comprising a second metal oxideprovided thereon, and the second transparent conductive layer is formedunder the condition different from that for forming the secondtransparent conductive layer.
 28. A transparent conductive film asdefined in claim 27, wherein the transparent conductive layer comprisingmetal oxide is an indium oxide-tin oxide (ITO) layer, or a zincoxide-aluminum oxide (ZAO) layer or an antimony oxide-tin oxide (ATO)layer.
 29. A process for the preparation of a transparent conductivefilm as defined in claim 27 or 28 comprising the steps of: forming thefirst transparent conductive layer comprising the first metal oxide ontothe polymer film by a vapor deposition process, and forming the secondtransparent conductive layer comprising the second metal oxide onto thefirst transparent conductive layer by a vapor deposition process underthe condition different from that for forming the first transparentconductive layer.
 30. A touch panel comprising an upper electrode havinga polymer film and a transparent conductive layer superposed in thisorder, and a lower electrode having a plastic or glass plate, a polymerfilm and a transparent conductive layer superposed in this order, theupper electrode and the lower electrode being bonded to each otherthrough spacers such that both of the transparent conductive layers faceeach other, wherein the upper electrode includes the transparentconductive film as defined in any of claims 23, 24, 27 and
 28. 31. Atouch panel comprising an upper electrode having a polymer film and afirst transparent conductive layer superposed in this order, and a lowerelectrode having a plastic or glass plate, a polymer film and a secondtransparent conductive layer superposed in this order, the upperelectrode and the lower electrode being bonded to each other throughspacers such that both of the transparent conductive layers face eachother, wherein the first transparent conductive layer of the upperelectrode is different in materials from the second transparentconductive layer of the lower electrode
 32. A touch panel comprising anupper electrode having a polymer film and a transparent conductive layersuperposed in this order, and a lower electrode having a plastic orglass plate, a polymer film and a transparent conductive layersuperposed in this order, the upper electrode and the lower electrodebeing bonded to each other through spacers such that both of thetransparent conductive layers face each other, wherein the lowerelectrode includes the transparent conductive film as defined in claim25.